Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /proc/sys/net/ipv4/* Variables: |
| 2 | |
| 3 | ip_forward - BOOLEAN |
| 4 | 0 - disabled (default) |
Jesper Dangaard Brouer | e18f5fe | 2009-02-23 04:39:04 +0000 | [diff] [blame] | 5 | not 0 - enabled |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6 | |
| 7 | Forward Packets between interfaces. |
| 8 | |
| 9 | This variable is special, its change resets all configuration |
| 10 | parameters to their default state (RFC1122 for hosts, RFC1812 |
| 11 | for routers) |
| 12 | |
| 13 | ip_default_ttl - INTEGER |
Eric Dumazet | cc6f02d | 2010-12-13 12:50:49 -0800 | [diff] [blame] | 14 | Default value of TTL field (Time To Live) for outgoing (but not |
| 15 | forwarded) IP packets. Should be between 1 and 255 inclusive. |
| 16 | Default: 64 (as recommended by RFC1700) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 17 | |
Hannes Frederic Sowa | cd174e6 | 2013-12-14 05:13:45 +0100 | [diff] [blame] | 18 | ip_no_pmtu_disc - INTEGER |
| 19 | Disable Path MTU Discovery. If enabled in mode 1 and a |
Hannes Frederic Sowa | 188b04d | 2013-12-14 04:42:13 +0100 | [diff] [blame] | 20 | fragmentation-required ICMP is received, the PMTU to this |
| 21 | destination will be set to min_pmtu (see below). You will need |
| 22 | to raise min_pmtu to the smallest interface MTU on your system |
| 23 | manually if you want to avoid locally generated fragments. |
Hannes Frederic Sowa | cd174e6 | 2013-12-14 05:13:45 +0100 | [diff] [blame] | 24 | |
| 25 | In mode 2 incoming Path MTU Discovery messages will be |
| 26 | discarded. Outgoing frames are handled the same as in mode 1, |
| 27 | implicitly setting IP_PMTUDISC_DONT on every created socket. |
| 28 | |
Hannes Frederic Sowa | 8ed1dc4 | 2014-01-09 10:01:17 +0100 | [diff] [blame] | 29 | Mode 3 is a hardend pmtu discover mode. The kernel will only |
| 30 | accept fragmentation-needed errors if the underlying protocol |
| 31 | can verify them besides a plain socket lookup. Current |
| 32 | protocols for which pmtu events will be honored are TCP, SCTP |
| 33 | and DCCP as they verify e.g. the sequence number or the |
| 34 | association. This mode should not be enabled globally but is |
| 35 | only intended to secure e.g. name servers in namespaces where |
| 36 | TCP path mtu must still work but path MTU information of other |
| 37 | protocols should be discarded. If enabled globally this mode |
| 38 | could break other protocols. |
| 39 | |
| 40 | Possible values: 0-3 |
Hannes Frederic Sowa | 188b04d | 2013-12-14 04:42:13 +0100 | [diff] [blame] | 41 | Default: FALSE |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 42 | |
| 43 | min_pmtu - INTEGER |
Eric Dumazet | 20db93c | 2011-11-08 14:21:44 -0500 | [diff] [blame] | 44 | default 552 - minimum discovered Path MTU |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 45 | |
Hannes Frederic Sowa | f87c10a | 2014-01-09 10:01:15 +0100 | [diff] [blame] | 46 | ip_forward_use_pmtu - BOOLEAN |
| 47 | By default we don't trust protocol path MTUs while forwarding |
| 48 | because they could be easily forged and can lead to unwanted |
| 49 | fragmentation by the router. |
| 50 | You only need to enable this if you have user-space software |
| 51 | which tries to discover path mtus by itself and depends on the |
| 52 | kernel honoring this information. This is normally not the |
| 53 | case. |
| 54 | Default: 0 (disabled) |
| 55 | Possible values: |
| 56 | 0 - disabled |
| 57 | 1 - enabled |
| 58 | |
Loganaden Velvindron | 219b5f2 | 2014-11-04 03:02:49 -0800 | [diff] [blame] | 59 | fwmark_reflect - BOOLEAN |
| 60 | Controls the fwmark of kernel-generated IPv4 reply packets that are not |
| 61 | associated with a socket for example, TCP RSTs or ICMP echo replies). |
| 62 | If unset, these packets have a fwmark of zero. If set, they have the |
| 63 | fwmark of the packet they are replying to. |
| 64 | Default: 0 |
| 65 | |
Ben Greear | cbaf087 | 2010-11-08 09:13:48 +0000 | [diff] [blame] | 66 | route/max_size - INTEGER |
| 67 | Maximum number of routes allowed in the kernel. Increase |
| 68 | this when using large numbers of interfaces and/or routes. |
Ani Sinha | 25050c6 | 2015-01-07 15:45:56 -0800 | [diff] [blame] | 69 | From linux kernel 3.6 onwards, this is deprecated for ipv4 |
| 70 | as route cache is no longer used. |
Ben Greear | cbaf087 | 2010-11-08 09:13:48 +0000 | [diff] [blame] | 71 | |
YOSHIFUJI Hideaki / 吉藤英明 | 2724680 | 2013-01-22 05:20:05 +0000 | [diff] [blame] | 72 | neigh/default/gc_thresh1 - INTEGER |
| 73 | Minimum number of entries to keep. Garbage collector will not |
| 74 | purge entries if there are fewer than this number. |
Li RongQing | b66c66d | 2013-03-14 22:49:47 +0000 | [diff] [blame] | 75 | Default: 128 |
YOSHIFUJI Hideaki / 吉藤英明 | 2724680 | 2013-01-22 05:20:05 +0000 | [diff] [blame] | 76 | |
stephen hemminger | a3d1214 | 2014-08-25 15:05:30 -0700 | [diff] [blame] | 77 | neigh/default/gc_thresh2 - INTEGER |
| 78 | Threshold when garbage collector becomes more aggressive about |
| 79 | purging entries. Entries older than 5 seconds will be cleared |
| 80 | when over this number. |
| 81 | Default: 512 |
| 82 | |
Ben Greear | cbaf087 | 2010-11-08 09:13:48 +0000 | [diff] [blame] | 83 | neigh/default/gc_thresh3 - INTEGER |
| 84 | Maximum number of neighbor entries allowed. Increase this |
| 85 | when using large numbers of interfaces and when communicating |
| 86 | with large numbers of directly-connected peers. |
Shan Wei | cc86802 | 2012-12-04 18:50:35 +0000 | [diff] [blame] | 87 | Default: 1024 |
Ben Greear | cbaf087 | 2010-11-08 09:13:48 +0000 | [diff] [blame] | 88 | |
Eric Dumazet | 8b5c171 | 2011-11-09 12:07:14 +0000 | [diff] [blame] | 89 | neigh/default/unres_qlen_bytes - INTEGER |
| 90 | The maximum number of bytes which may be used by packets |
| 91 | queued for each unresolved address by other network layers. |
| 92 | (added in linux 3.3) |
stephen hemminger | 3b09adc | 2013-01-03 07:50:29 +0000 | [diff] [blame] | 93 | Setting negative value is meaningless and will return error. |
Shan Wei | cc86802 | 2012-12-04 18:50:35 +0000 | [diff] [blame] | 94 | Default: 65536 Bytes(64KB) |
Eric Dumazet | 8b5c171 | 2011-11-09 12:07:14 +0000 | [diff] [blame] | 95 | |
| 96 | neigh/default/unres_qlen - INTEGER |
| 97 | The maximum number of packets which may be queued for each |
| 98 | unresolved address by other network layers. |
| 99 | (deprecated in linux 3.3) : use unres_qlen_bytes instead. |
Shan Wei | cc86802 | 2012-12-04 18:50:35 +0000 | [diff] [blame] | 100 | Prior to linux 3.3, the default value is 3 which may cause |
Shan Wei | 5d248c4 | 2012-12-06 16:27:51 +0000 | [diff] [blame] | 101 | unexpected packet loss. The current default value is calculated |
Shan Wei | cc86802 | 2012-12-04 18:50:35 +0000 | [diff] [blame] | 102 | according to default value of unres_qlen_bytes and true size of |
| 103 | packet. |
| 104 | Default: 31 |
Eric Dumazet | 8b5c171 | 2011-11-09 12:07:14 +0000 | [diff] [blame] | 105 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 106 | mtu_expires - INTEGER |
| 107 | Time, in seconds, that cached PMTU information is kept. |
| 108 | |
| 109 | min_adv_mss - INTEGER |
| 110 | The advertised MSS depends on the first hop route MTU, but will |
| 111 | never be lower than this setting. |
| 112 | |
| 113 | IP Fragmentation: |
| 114 | |
| 115 | ipfrag_high_thresh - INTEGER |
Jesper Dangaard Brouer | e18f5fe | 2009-02-23 04:39:04 +0000 | [diff] [blame] | 116 | Maximum memory used to reassemble IP fragments. When |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 117 | ipfrag_high_thresh bytes of memory is allocated for this purpose, |
| 118 | the fragment handler will toss packets until ipfrag_low_thresh |
Nikolay Aleksandrov | 1bab4c7 | 2014-07-24 16:50:37 +0200 | [diff] [blame] | 119 | is reached. This also serves as a maximum limit to namespaces |
| 120 | different from the initial one. |
Jesper Dangaard Brouer | e18f5fe | 2009-02-23 04:39:04 +0000 | [diff] [blame] | 121 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 122 | ipfrag_low_thresh - INTEGER |
Florian Westphal | b13d3cb | 2014-07-24 16:50:32 +0200 | [diff] [blame] | 123 | Maximum memory used to reassemble IP fragments before the kernel |
| 124 | begins to remove incomplete fragment queues to free up resources. |
| 125 | The kernel still accepts new fragments for defragmentation. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 126 | |
| 127 | ipfrag_time - INTEGER |
Jesper Dangaard Brouer | e18f5fe | 2009-02-23 04:39:04 +0000 | [diff] [blame] | 128 | Time in seconds to keep an IP fragment in memory. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 129 | |
Herbert Xu | 89cee8b | 2005-12-13 23:14:27 -0800 | [diff] [blame] | 130 | ipfrag_max_dist - INTEGER |
Jesper Dangaard Brouer | e18f5fe | 2009-02-23 04:39:04 +0000 | [diff] [blame] | 131 | ipfrag_max_dist is a non-negative integer value which defines the |
| 132 | maximum "disorder" which is allowed among fragments which share a |
| 133 | common IP source address. Note that reordering of packets is |
| 134 | not unusual, but if a large number of fragments arrive from a source |
| 135 | IP address while a particular fragment queue remains incomplete, it |
| 136 | probably indicates that one or more fragments belonging to that queue |
| 137 | have been lost. When ipfrag_max_dist is positive, an additional check |
| 138 | is done on fragments before they are added to a reassembly queue - if |
| 139 | ipfrag_max_dist (or more) fragments have arrived from a particular IP |
| 140 | address between additions to any IP fragment queue using that source |
| 141 | address, it's presumed that one or more fragments in the queue are |
| 142 | lost. The existing fragment queue will be dropped, and a new one |
Herbert Xu | 89cee8b | 2005-12-13 23:14:27 -0800 | [diff] [blame] | 143 | started. An ipfrag_max_dist value of zero disables this check. |
| 144 | |
| 145 | Using a very small value, e.g. 1 or 2, for ipfrag_max_dist can |
| 146 | result in unnecessarily dropping fragment queues when normal |
Jesper Dangaard Brouer | e18f5fe | 2009-02-23 04:39:04 +0000 | [diff] [blame] | 147 | reordering of packets occurs, which could lead to poor application |
| 148 | performance. Using a very large value, e.g. 50000, increases the |
| 149 | likelihood of incorrectly reassembling IP fragments that originate |
Herbert Xu | 89cee8b | 2005-12-13 23:14:27 -0800 | [diff] [blame] | 150 | from different IP datagrams, which could result in data corruption. |
| 151 | Default: 64 |
| 152 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 153 | INET peer storage: |
| 154 | |
| 155 | inet_peer_threshold - INTEGER |
Jesper Dangaard Brouer | e18f5fe | 2009-02-23 04:39:04 +0000 | [diff] [blame] | 156 | The approximate size of the storage. Starting from this threshold |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 157 | entries will be thrown aggressively. This threshold also determines |
| 158 | entries' time-to-live and time intervals between garbage collection |
| 159 | passes. More entries, less time-to-live, less GC interval. |
| 160 | |
| 161 | inet_peer_minttl - INTEGER |
| 162 | Minimum time-to-live of entries. Should be enough to cover fragment |
| 163 | time-to-live on the reassembling side. This minimum time-to-live is |
| 164 | guaranteed if the pool size is less than inet_peer_threshold. |
Stephen Hemminger | 77a538d | 2008-07-01 17:22:48 -0700 | [diff] [blame] | 165 | Measured in seconds. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 166 | |
| 167 | inet_peer_maxttl - INTEGER |
| 168 | Maximum time-to-live of entries. Unused entries will expire after |
| 169 | this period of time if there is no memory pressure on the pool (i.e. |
| 170 | when the number of entries in the pool is very small). |
Stephen Hemminger | 77a538d | 2008-07-01 17:22:48 -0700 | [diff] [blame] | 171 | Measured in seconds. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 172 | |
Jesper Dangaard Brouer | e18f5fe | 2009-02-23 04:39:04 +0000 | [diff] [blame] | 173 | TCP variables: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 174 | |
Stephen Hemminger | ef56e62 | 2006-11-09 16:37:26 -0800 | [diff] [blame] | 175 | somaxconn - INTEGER |
| 176 | Limit of socket listen() backlog, known in userspace as SOMAXCONN. |
| 177 | Defaults to 128. See also tcp_max_syn_backlog for additional tuning |
| 178 | for TCP sockets. |
| 179 | |
Stephen Hemminger | ef56e62 | 2006-11-09 16:37:26 -0800 | [diff] [blame] | 180 | tcp_abort_on_overflow - BOOLEAN |
| 181 | If listening service is too slow to accept new connections, |
| 182 | reset them. Default state is FALSE. It means that if overflow |
| 183 | occurred due to a burst, connection will recover. Enable this |
| 184 | option _only_ if you are really sure that listening daemon |
| 185 | cannot be tuned to accept connections faster. Enabling this |
| 186 | option can harm clients of your server. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 187 | |
Stephen Hemminger | ef56e62 | 2006-11-09 16:37:26 -0800 | [diff] [blame] | 188 | tcp_adv_win_scale - INTEGER |
| 189 | Count buffering overhead as bytes/2^tcp_adv_win_scale |
| 190 | (if tcp_adv_win_scale > 0) or bytes-bytes/2^(-tcp_adv_win_scale), |
| 191 | if it is <= 0. |
Alexey Dobriyan | 0147fc0 | 2010-11-22 12:54:21 +0000 | [diff] [blame] | 192 | Possible values are [-31, 31], inclusive. |
Eric Dumazet | b49960a | 2012-05-02 02:28:41 +0000 | [diff] [blame] | 193 | Default: 1 |
Stephen Hemminger | ef56e62 | 2006-11-09 16:37:26 -0800 | [diff] [blame] | 194 | |
| 195 | tcp_allowed_congestion_control - STRING |
| 196 | Show/set the congestion control choices available to non-privileged |
| 197 | processes. The list is a subset of those listed in |
| 198 | tcp_available_congestion_control. |
| 199 | Default is "reno" and the default setting (tcp_congestion_control). |
| 200 | |
| 201 | tcp_app_win - INTEGER |
| 202 | Reserve max(window/2^tcp_app_win, mss) of window for application |
| 203 | buffer. Value 0 is special, it means that nothing is reserved. |
| 204 | Default: 31 |
| 205 | |
Eric Dumazet | f54b311 | 2013-12-05 22:36:05 -0800 | [diff] [blame] | 206 | tcp_autocorking - BOOLEAN |
| 207 | Enable TCP auto corking : |
| 208 | When applications do consecutive small write()/sendmsg() system calls, |
| 209 | we try to coalesce these small writes as much as possible, to lower |
| 210 | total amount of sent packets. This is done if at least one prior |
| 211 | packet for the flow is waiting in Qdisc queues or device transmit |
| 212 | queue. Applications can still use TCP_CORK for optimal behavior |
| 213 | when they know how/when to uncork their sockets. |
| 214 | Default : 1 |
| 215 | |
Stephen Hemminger | ef56e62 | 2006-11-09 16:37:26 -0800 | [diff] [blame] | 216 | tcp_available_congestion_control - STRING |
| 217 | Shows the available congestion control choices that are registered. |
| 218 | More congestion control algorithms may be available as modules, |
| 219 | but not loaded. |
| 220 | |
John Heffner | 71599cd | 2007-02-27 10:03:56 -0800 | [diff] [blame] | 221 | tcp_base_mss - INTEGER |
Stephen Hemminger | 4edc2f3 | 2008-07-10 16:50:26 -0700 | [diff] [blame] | 222 | The initial value of search_low to be used by the packetization layer |
| 223 | Path MTU discovery (MTU probing). If MTU probing is enabled, |
| 224 | this is the initial MSS used by the connection. |
John Heffner | 71599cd | 2007-02-27 10:03:56 -0800 | [diff] [blame] | 225 | |
Stephen Hemminger | ef56e62 | 2006-11-09 16:37:26 -0800 | [diff] [blame] | 226 | tcp_congestion_control - STRING |
| 227 | Set the congestion control algorithm to be used for new |
| 228 | connections. The algorithm "reno" is always available, but |
| 229 | additional choices may be available based on kernel configuration. |
| 230 | Default is set as part of kernel configuration. |
Eric Dumazet | d8a6e65 | 2011-11-30 01:02:41 +0000 | [diff] [blame] | 231 | For passive connections, the listener congestion control choice |
| 232 | is inherited. |
| 233 | [see setsockopt(listenfd, SOL_TCP, TCP_CONGESTION, "name" ...) ] |
Stephen Hemminger | ef56e62 | 2006-11-09 16:37:26 -0800 | [diff] [blame] | 234 | |
| 235 | tcp_dsack - BOOLEAN |
| 236 | Allows TCP to send "duplicate" SACKs. |
| 237 | |
Yuchung Cheng | eed530b | 2012-05-02 13:30:03 +0000 | [diff] [blame] | 238 | tcp_early_retrans - INTEGER |
| 239 | Enable Early Retransmit (ER), per RFC 5827. ER lowers the threshold |
| 240 | for triggering fast retransmit when the amount of outstanding data is |
| 241 | small and when no previously unsent data can be transmitted (such |
Nandita Dukkipati | 6ba8a3b | 2013-03-11 10:00:43 +0000 | [diff] [blame] | 242 | that limited transmit could be used). Also controls the use of |
Masanari Iida | 3dd17ed | 2013-05-24 07:05:59 +0000 | [diff] [blame] | 243 | Tail loss probe (TLP) that converts RTOs occurring due to tail |
Nandita Dukkipati | 6ba8a3b | 2013-03-11 10:00:43 +0000 | [diff] [blame] | 244 | losses into fast recovery (draft-dukkipati-tcpm-tcp-loss-probe-01). |
Yuchung Cheng | eed530b | 2012-05-02 13:30:03 +0000 | [diff] [blame] | 245 | Possible values: |
| 246 | 0 disables ER |
| 247 | 1 enables ER |
| 248 | 2 enables ER but delays fast recovery and fast retransmit |
| 249 | by a fourth of RTT. This mitigates connection falsely |
| 250 | recovers when network has a small degree of reordering |
| 251 | (less than 3 packets). |
Nandita Dukkipati | 6ba8a3b | 2013-03-11 10:00:43 +0000 | [diff] [blame] | 252 | 3 enables delayed ER and TLP. |
| 253 | 4 enables TLP only. |
| 254 | Default: 3 |
Yuchung Cheng | eed530b | 2012-05-02 13:30:03 +0000 | [diff] [blame] | 255 | |
Peter Chubb | 34a6ef3 | 2011-02-02 15:39:58 -0800 | [diff] [blame] | 256 | tcp_ecn - INTEGER |
Rick Jones | 7e3a2dc | 2012-11-28 09:53:10 +0000 | [diff] [blame] | 257 | Control use of Explicit Congestion Notification (ECN) by TCP. |
| 258 | ECN is used only when both ends of the TCP connection indicate |
| 259 | support for it. This feature is useful in avoiding losses due |
| 260 | to congestion by allowing supporting routers to signal |
| 261 | congestion before having to drop packets. |
Ilpo Järvinen | 255cac9 | 2009-05-04 11:07:36 -0700 | [diff] [blame] | 262 | Possible values are: |
Rick Jones | 7e3a2dc | 2012-11-28 09:53:10 +0000 | [diff] [blame] | 263 | 0 Disable ECN. Neither initiate nor accept ECN. |
Vijay Subramanian | 3d55b32 | 2013-01-09 12:21:30 +0000 | [diff] [blame] | 264 | 1 Enable ECN when requested by incoming connections and |
| 265 | also request ECN on outgoing connection attempts. |
| 266 | 2 Enable ECN when requested by incoming connections |
Rick Jones | 7e3a2dc | 2012-11-28 09:53:10 +0000 | [diff] [blame] | 267 | but do not request ECN on outgoing connections. |
Ilpo Järvinen | 255cac9 | 2009-05-04 11:07:36 -0700 | [diff] [blame] | 268 | Default: 2 |
Stephen Hemminger | ef56e62 | 2006-11-09 16:37:26 -0800 | [diff] [blame] | 269 | |
| 270 | tcp_fack - BOOLEAN |
| 271 | Enable FACK congestion avoidance and fast retransmission. |
| 272 | The value is not used, if tcp_sack is not enabled. |
| 273 | |
| 274 | tcp_fin_timeout - INTEGER |
Rick Jones | d825da2 | 2012-12-10 11:33:00 +0000 | [diff] [blame] | 275 | The length of time an orphaned (no longer referenced by any |
| 276 | application) connection will remain in the FIN_WAIT_2 state |
| 277 | before it is aborted at the local end. While a perfectly |
| 278 | valid "receive only" state for an un-orphaned connection, an |
| 279 | orphaned connection in FIN_WAIT_2 state could otherwise wait |
| 280 | forever for the remote to close its end of the connection. |
| 281 | Cf. tcp_max_orphans |
| 282 | Default: 60 seconds |
Stephen Hemminger | ef56e62 | 2006-11-09 16:37:26 -0800 | [diff] [blame] | 283 | |
Ilpo Järvinen | 8980806 | 2007-02-27 10:10:55 -0800 | [diff] [blame] | 284 | tcp_frto - INTEGER |
Yuchung Cheng | e33099f | 2013-03-20 13:33:00 +0000 | [diff] [blame] | 285 | Enables Forward RTO-Recovery (F-RTO) defined in RFC5682. |
Ilpo Järvinen | cd99889 | 2007-09-20 11:35:26 -0700 | [diff] [blame] | 286 | F-RTO is an enhanced recovery algorithm for TCP retransmission |
Yuchung Cheng | e33099f | 2013-03-20 13:33:00 +0000 | [diff] [blame] | 287 | timeouts. It is particularly beneficial in networks where the |
| 288 | RTT fluctuates (e.g., wireless). F-RTO is sender-side only |
| 289 | modification. It does not require any support from the peer. |
Stephen Hemminger | 4edc2f3 | 2008-07-10 16:50:26 -0700 | [diff] [blame] | 290 | |
Yuchung Cheng | e33099f | 2013-03-20 13:33:00 +0000 | [diff] [blame] | 291 | By default it's enabled with a non-zero value. 0 disables F-RTO. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 292 | |
| 293 | tcp_keepalive_time - INTEGER |
| 294 | How often TCP sends out keepalive messages when keepalive is enabled. |
| 295 | Default: 2hours. |
| 296 | |
| 297 | tcp_keepalive_probes - INTEGER |
| 298 | How many keepalive probes TCP sends out, until it decides that the |
| 299 | connection is broken. Default value: 9. |
| 300 | |
| 301 | tcp_keepalive_intvl - INTEGER |
| 302 | How frequently the probes are send out. Multiplied by |
| 303 | tcp_keepalive_probes it is time to kill not responding connection, |
| 304 | after probes started. Default value: 75sec i.e. connection |
| 305 | will be aborted after ~11 minutes of retries. |
| 306 | |
Stephen Hemminger | ef56e62 | 2006-11-09 16:37:26 -0800 | [diff] [blame] | 307 | tcp_low_latency - BOOLEAN |
| 308 | If set, the TCP stack makes decisions that prefer lower |
| 309 | latency as opposed to higher throughput. By default, this |
| 310 | option is not set meaning that higher throughput is preferred. |
| 311 | An example of an application where this default should be |
| 312 | changed would be a Beowulf compute cluster. |
| 313 | Default: 0 |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 314 | |
| 315 | tcp_max_orphans - INTEGER |
| 316 | Maximal number of TCP sockets not attached to any user file handle, |
| 317 | held by system. If this number is exceeded orphaned connections are |
| 318 | reset immediately and warning is printed. This limit exists |
| 319 | only to prevent simple DoS attacks, you _must_ not rely on this |
| 320 | or lower the limit artificially, but rather increase it |
| 321 | (probably, after increasing installed memory), |
| 322 | if network conditions require more than default value, |
| 323 | and tune network services to linger and kill such states |
| 324 | more aggressively. Let me to remind again: each orphan eats |
| 325 | up to ~64K of unswappable memory. |
| 326 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 327 | tcp_max_syn_backlog - INTEGER |
Peter Pan(潘卫平) | 99b53bd | 2011-12-05 21:39:41 +0000 | [diff] [blame] | 328 | Maximal number of remembered connection requests, which have not |
| 329 | received an acknowledgment from connecting client. |
| 330 | The minimal value is 128 for low memory machines, and it will |
| 331 | increase in proportion to the memory of machine. |
| 332 | If server suffers from overload, try increasing this number. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 333 | |
Stephen Hemminger | ef56e62 | 2006-11-09 16:37:26 -0800 | [diff] [blame] | 334 | tcp_max_tw_buckets - INTEGER |
| 335 | Maximal number of timewait sockets held by system simultaneously. |
| 336 | If this number is exceeded time-wait socket is immediately destroyed |
| 337 | and warning is printed. This limit exists only to prevent |
| 338 | simple DoS attacks, you _must_ not lower the limit artificially, |
| 339 | but rather increase it (probably, after increasing installed memory), |
| 340 | if network conditions require more than default value. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 341 | |
Stephen Hemminger | ef56e62 | 2006-11-09 16:37:26 -0800 | [diff] [blame] | 342 | tcp_mem - vector of 3 INTEGERs: min, pressure, max |
| 343 | min: below this number of pages TCP is not bothered about its |
| 344 | memory appetite. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 345 | |
Stephen Hemminger | ef56e62 | 2006-11-09 16:37:26 -0800 | [diff] [blame] | 346 | pressure: when amount of memory allocated by TCP exceeds this number |
| 347 | of pages, TCP moderates its memory consumption and enters memory |
| 348 | pressure mode, which is exited when memory consumption falls |
| 349 | under "min". |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 350 | |
Stephen Hemminger | ef56e62 | 2006-11-09 16:37:26 -0800 | [diff] [blame] | 351 | max: number of pages allowed for queueing by all TCP sockets. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 352 | |
Stephen Hemminger | ef56e62 | 2006-11-09 16:37:26 -0800 | [diff] [blame] | 353 | Defaults are calculated at boot time from amount of available |
| 354 | memory. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 355 | |
John Heffner | 71599cd | 2007-02-27 10:03:56 -0800 | [diff] [blame] | 356 | tcp_moderate_rcvbuf - BOOLEAN |
Stephen Hemminger | 4edc2f3 | 2008-07-10 16:50:26 -0700 | [diff] [blame] | 357 | If set, TCP performs receive buffer auto-tuning, attempting to |
John Heffner | 71599cd | 2007-02-27 10:03:56 -0800 | [diff] [blame] | 358 | automatically size the buffer (no greater than tcp_rmem[2]) to |
| 359 | match the size required by the path for full throughput. Enabled by |
| 360 | default. |
| 361 | |
| 362 | tcp_mtu_probing - INTEGER |
| 363 | Controls TCP Packetization-Layer Path MTU Discovery. Takes three |
| 364 | values: |
| 365 | 0 - Disabled |
| 366 | 1 - Disabled by default, enabled when an ICMP black hole detected |
| 367 | 2 - Always enabled, use initial MSS of tcp_base_mss. |
| 368 | |
| 369 | tcp_no_metrics_save - BOOLEAN |
| 370 | By default, TCP saves various connection metrics in the route cache |
| 371 | when the connection closes, so that connections established in the |
| 372 | near future can use these to set initial conditions. Usually, this |
| 373 | increases overall performance, but may sometimes cause performance |
Simon Arlott | 0f035b8 | 2007-10-20 01:30:25 +0200 | [diff] [blame] | 374 | degradation. If set, TCP will not cache metrics on closing |
John Heffner | 71599cd | 2007-02-27 10:03:56 -0800 | [diff] [blame] | 375 | connections. |
| 376 | |
Stephen Hemminger | ef56e62 | 2006-11-09 16:37:26 -0800 | [diff] [blame] | 377 | tcp_orphan_retries - INTEGER |
Damian Lukowski | 5d78922 | 2009-09-01 10:24:04 +0000 | [diff] [blame] | 378 | This value influences the timeout of a locally closed TCP connection, |
| 379 | when RTO retransmissions remain unacknowledged. |
| 380 | See tcp_retries2 for more details. |
| 381 | |
David S. Miller | 06b8fc5 | 2011-07-08 09:31:31 -0700 | [diff] [blame] | 382 | The default value is 8. |
Damian Lukowski | 5d78922 | 2009-09-01 10:24:04 +0000 | [diff] [blame] | 383 | If your machine is a loaded WEB server, |
Stephen Hemminger | ef56e62 | 2006-11-09 16:37:26 -0800 | [diff] [blame] | 384 | you should think about lowering this value, such sockets |
| 385 | may consume significant resources. Cf. tcp_max_orphans. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 386 | |
| 387 | tcp_reordering - INTEGER |
Eric Dumazet | dca145f | 2014-10-27 21:45:24 -0700 | [diff] [blame] | 388 | Initial reordering level of packets in a TCP stream. |
| 389 | TCP stack can then dynamically adjust flow reordering level |
| 390 | between this initial value and tcp_max_reordering |
Jesper Dangaard Brouer | e18f5fe | 2009-02-23 04:39:04 +0000 | [diff] [blame] | 391 | Default: 3 |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 392 | |
Eric Dumazet | dca145f | 2014-10-27 21:45:24 -0700 | [diff] [blame] | 393 | tcp_max_reordering - INTEGER |
| 394 | Maximal reordering level of packets in a TCP stream. |
| 395 | 300 is a fairly conservative value, but you might increase it |
| 396 | if paths are using per packet load balancing (like bonding rr mode) |
| 397 | Default: 300 |
| 398 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 399 | tcp_retrans_collapse - BOOLEAN |
| 400 | Bug-to-bug compatibility with some broken printers. |
| 401 | On retransmit try to send bigger packets to work around bugs in |
| 402 | certain TCP stacks. |
| 403 | |
Stephen Hemminger | ef56e62 | 2006-11-09 16:37:26 -0800 | [diff] [blame] | 404 | tcp_retries1 - INTEGER |
Damian Lukowski | 5d78922 | 2009-09-01 10:24:04 +0000 | [diff] [blame] | 405 | This value influences the time, after which TCP decides, that |
| 406 | something is wrong due to unacknowledged RTO retransmissions, |
| 407 | and reports this suspicion to the network layer. |
| 408 | See tcp_retries2 for more details. |
| 409 | |
| 410 | RFC 1122 recommends at least 3 retransmissions, which is the |
| 411 | default. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 412 | |
Stephen Hemminger | ef56e62 | 2006-11-09 16:37:26 -0800 | [diff] [blame] | 413 | tcp_retries2 - INTEGER |
Damian Lukowski | 5d78922 | 2009-09-01 10:24:04 +0000 | [diff] [blame] | 414 | This value influences the timeout of an alive TCP connection, |
| 415 | when RTO retransmissions remain unacknowledged. |
| 416 | Given a value of N, a hypothetical TCP connection following |
| 417 | exponential backoff with an initial RTO of TCP_RTO_MIN would |
| 418 | retransmit N times before killing the connection at the (N+1)th RTO. |
| 419 | |
| 420 | The default value of 15 yields a hypothetical timeout of 924.6 |
| 421 | seconds and is a lower bound for the effective timeout. |
| 422 | TCP will effectively time out at the first RTO which exceeds the |
| 423 | hypothetical timeout. |
| 424 | |
| 425 | RFC 1122 recommends at least 100 seconds for the timeout, |
| 426 | which corresponds to a value of at least 8. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 427 | |
Stephen Hemminger | ef56e62 | 2006-11-09 16:37:26 -0800 | [diff] [blame] | 428 | tcp_rfc1337 - BOOLEAN |
| 429 | If set, the TCP stack behaves conforming to RFC1337. If unset, |
| 430 | we are not conforming to RFC, but prevent TCP TIME_WAIT |
| 431 | assassination. |
| 432 | Default: 0 |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 433 | |
| 434 | tcp_rmem - vector of 3 INTEGERs: min, default, max |
| 435 | min: Minimal size of receive buffer used by TCP sockets. |
| 436 | It is guaranteed to each TCP socket, even under moderate memory |
| 437 | pressure. |
Max Matveev | 6539fef | 2011-06-21 21:18:13 +0000 | [diff] [blame] | 438 | Default: 1 page |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 439 | |
J. Bruce Fields | 53025f5 | 2008-07-10 16:47:41 -0700 | [diff] [blame] | 440 | default: initial size of receive buffer used by TCP sockets. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 441 | This value overrides net.core.rmem_default used by other protocols. |
| 442 | Default: 87380 bytes. This value results in window of 65535 with |
| 443 | default setting of tcp_adv_win_scale and tcp_app_win:0 and a bit |
| 444 | less for default tcp_app_win. See below about these variables. |
| 445 | |
| 446 | max: maximal size of receive buffer allowed for automatically |
| 447 | selected receiver buffers for TCP socket. This value does not override |
J. Bruce Fields | 53025f5 | 2008-07-10 16:47:41 -0700 | [diff] [blame] | 448 | net.core.rmem_max. Calling setsockopt() with SO_RCVBUF disables |
| 449 | automatic tuning of that socket's receive buffer size, in which |
| 450 | case this value is ignored. |
Eric Dumazet | b49960a | 2012-05-02 02:28:41 +0000 | [diff] [blame] | 451 | Default: between 87380B and 6MB, depending on RAM size. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 452 | |
Stephen Hemminger | ef56e62 | 2006-11-09 16:37:26 -0800 | [diff] [blame] | 453 | tcp_sack - BOOLEAN |
| 454 | Enable select acknowledgments (SACKS). |
Rick Jones | 15d99e0 | 2006-03-20 22:40:29 -0800 | [diff] [blame] | 455 | |
David S. Miller | 35089bb | 2006-06-13 22:33:04 -0700 | [diff] [blame] | 456 | tcp_slow_start_after_idle - BOOLEAN |
| 457 | If set, provide RFC2861 behavior and time out the congestion |
| 458 | window after an idle period. An idle period is defined at |
| 459 | the current RTO. If unset, the congestion window will not |
| 460 | be timed out after an idle period. |
| 461 | Default: 1 |
| 462 | |
Stephen Hemminger | ef56e62 | 2006-11-09 16:37:26 -0800 | [diff] [blame] | 463 | tcp_stdurg - BOOLEAN |
Stephen Hemminger | 4edc2f3 | 2008-07-10 16:50:26 -0700 | [diff] [blame] | 464 | Use the Host requirements interpretation of the TCP urgent pointer field. |
Stephen Hemminger | ef56e62 | 2006-11-09 16:37:26 -0800 | [diff] [blame] | 465 | Most hosts use the older BSD interpretation, so if you turn this on |
| 466 | Linux might not communicate correctly with them. |
| 467 | Default: FALSE |
| 468 | |
| 469 | tcp_synack_retries - INTEGER |
| 470 | Number of times SYNACKs for a passive TCP connection attempt will |
| 471 | be retransmitted. Should not be higher than 255. Default value |
Alex Bergmann | 6c9ff97 | 2012-08-31 02:48:31 +0000 | [diff] [blame] | 472 | is 5, which corresponds to 31seconds till the last retransmission |
| 473 | with the current initial RTO of 1second. With this the final timeout |
| 474 | for a passive TCP connection will happen after 63seconds. |
Stephen Hemminger | ef56e62 | 2006-11-09 16:37:26 -0800 | [diff] [blame] | 475 | |
| 476 | tcp_syncookies - BOOLEAN |
Shan Wei | a3c910d | 2013-06-21 15:18:32 +0800 | [diff] [blame] | 477 | Only valid when the kernel was compiled with CONFIG_SYN_COOKIES |
Stephen Hemminger | ef56e62 | 2006-11-09 16:37:26 -0800 | [diff] [blame] | 478 | Send out syncookies when the syn backlog queue of a socket |
Stephen Hemminger | 4edc2f3 | 2008-07-10 16:50:26 -0700 | [diff] [blame] | 479 | overflows. This is to prevent against the common 'SYN flood attack' |
Shan Wei | a3c910d | 2013-06-21 15:18:32 +0800 | [diff] [blame] | 480 | Default: 1 |
Stephen Hemminger | ef56e62 | 2006-11-09 16:37:26 -0800 | [diff] [blame] | 481 | |
| 482 | Note, that syncookies is fallback facility. |
| 483 | It MUST NOT be used to help highly loaded servers to stand |
Stephen Hemminger | 4edc2f3 | 2008-07-10 16:50:26 -0700 | [diff] [blame] | 484 | against legal connection rate. If you see SYN flood warnings |
Stephen Hemminger | ef56e62 | 2006-11-09 16:37:26 -0800 | [diff] [blame] | 485 | in your logs, but investigation shows that they occur |
| 486 | because of overload with legal connections, you should tune |
| 487 | another parameters until this warning disappear. |
| 488 | See: tcp_max_syn_backlog, tcp_synack_retries, tcp_abort_on_overflow. |
| 489 | |
| 490 | syncookies seriously violate TCP protocol, do not allow |
| 491 | to use TCP extensions, can result in serious degradation |
| 492 | of some services (f.e. SMTP relaying), visible not by you, |
| 493 | but your clients and relays, contacting you. While you see |
Stephen Hemminger | 4edc2f3 | 2008-07-10 16:50:26 -0700 | [diff] [blame] | 494 | SYN flood warnings in logs not being really flooded, your server |
Stephen Hemminger | ef56e62 | 2006-11-09 16:37:26 -0800 | [diff] [blame] | 495 | is seriously misconfigured. |
| 496 | |
Hannes Frederic Sowa | 5ad37d5 | 2013-07-26 17:43:23 +0200 | [diff] [blame] | 497 | If you want to test which effects syncookies have to your |
| 498 | network connections you can set this knob to 2 to enable |
| 499 | unconditionally generation of syncookies. |
| 500 | |
Yuchung Cheng | cf60af0 | 2012-07-19 06:43:09 +0000 | [diff] [blame] | 501 | tcp_fastopen - INTEGER |
| 502 | Enable TCP Fast Open feature (draft-ietf-tcpm-fastopen) to send data |
| 503 | in the opening SYN packet. To use this feature, the client application |
Jerry Chu | 1046716 | 2012-08-31 12:29:11 +0000 | [diff] [blame] | 504 | must use sendmsg() or sendto() with MSG_FASTOPEN flag rather than |
| 505 | connect() to perform a TCP handshake automatically. |
Yuchung Cheng | cf60af0 | 2012-07-19 06:43:09 +0000 | [diff] [blame] | 506 | |
Jerry Chu | 1046716 | 2012-08-31 12:29:11 +0000 | [diff] [blame] | 507 | The values (bitmap) are |
Yuchung Cheng | 0d41cca | 2013-10-31 09:19:32 -0700 | [diff] [blame] | 508 | 1: Enables sending data in the opening SYN on the client w/ MSG_FASTOPEN. |
Jerry Chu | 1046716 | 2012-08-31 12:29:11 +0000 | [diff] [blame] | 509 | 2: Enables TCP Fast Open on the server side, i.e., allowing data in |
| 510 | a SYN packet to be accepted and passed to the application before |
| 511 | 3-way hand shake finishes. |
| 512 | 4: Send data in the opening SYN regardless of cookie availability and |
| 513 | without a cookie option. |
| 514 | 0x100: Accept SYN data w/o validating the cookie. |
| 515 | 0x200: Accept data-in-SYN w/o any cookie option present. |
| 516 | 0x400/0x800: Enable Fast Open on all listeners regardless of the |
| 517 | TCP_FASTOPEN socket option. The two different flags designate two |
| 518 | different ways of setting max_qlen without the TCP_FASTOPEN socket |
| 519 | option. |
Yuchung Cheng | cf60af0 | 2012-07-19 06:43:09 +0000 | [diff] [blame] | 520 | |
Yuchung Cheng | 0d41cca | 2013-10-31 09:19:32 -0700 | [diff] [blame] | 521 | Default: 1 |
Yuchung Cheng | cf60af0 | 2012-07-19 06:43:09 +0000 | [diff] [blame] | 522 | |
Jerry Chu | 1046716 | 2012-08-31 12:29:11 +0000 | [diff] [blame] | 523 | Note that the client & server side Fast Open flags (1 and 2 |
| 524 | respectively) must be also enabled before the rest of flags can take |
| 525 | effect. |
| 526 | |
| 527 | See include/net/tcp.h and the code for more details. |
| 528 | |
Stephen Hemminger | ef56e62 | 2006-11-09 16:37:26 -0800 | [diff] [blame] | 529 | tcp_syn_retries - INTEGER |
| 530 | Number of times initial SYNs for an active TCP connection attempt |
| 531 | will be retransmitted. Should not be higher than 255. Default value |
stephen hemminger | 3b09adc | 2013-01-03 07:50:29 +0000 | [diff] [blame] | 532 | is 6, which corresponds to 63seconds till the last retransmission |
Alex Bergmann | 6c9ff97 | 2012-08-31 02:48:31 +0000 | [diff] [blame] | 533 | with the current initial RTO of 1second. With this the final timeout |
| 534 | for an active TCP connection attempt will happen after 127seconds. |
Stephen Hemminger | ef56e62 | 2006-11-09 16:37:26 -0800 | [diff] [blame] | 535 | |
| 536 | tcp_timestamps - BOOLEAN |
| 537 | Enable timestamps as defined in RFC1323. |
| 538 | |
Eric Dumazet | 95bd09e | 2013-08-27 05:46:32 -0700 | [diff] [blame] | 539 | tcp_min_tso_segs - INTEGER |
| 540 | Minimal number of segments per TSO frame. |
| 541 | Since linux-3.12, TCP does an automatic sizing of TSO frames, |
| 542 | depending on flow rate, instead of filling 64Kbytes packets. |
| 543 | For specific usages, it's possible to force TCP to build big |
| 544 | TSO frames. Note that TCP stack might split too big TSO packets |
| 545 | if available window is too small. |
| 546 | Default: 2 |
| 547 | |
Stephen Hemminger | ef56e62 | 2006-11-09 16:37:26 -0800 | [diff] [blame] | 548 | tcp_tso_win_divisor - INTEGER |
| 549 | This allows control over what percentage of the congestion window |
| 550 | can be consumed by a single TSO frame. |
| 551 | The setting of this parameter is a choice between burstiness and |
| 552 | building larger TSO frames. |
| 553 | Default: 3 |
| 554 | |
| 555 | tcp_tw_recycle - BOOLEAN |
| 556 | Enable fast recycling TIME-WAIT sockets. Default value is 0. |
| 557 | It should not be changed without advice/request of technical |
| 558 | experts. |
| 559 | |
| 560 | tcp_tw_reuse - BOOLEAN |
| 561 | Allow to reuse TIME-WAIT sockets for new connections when it is |
| 562 | safe from protocol viewpoint. Default value is 0. |
| 563 | It should not be changed without advice/request of technical |
| 564 | experts. |
| 565 | |
| 566 | tcp_window_scaling - BOOLEAN |
| 567 | Enable window scaling as defined in RFC1323. |
| 568 | |
| 569 | tcp_wmem - vector of 3 INTEGERs: min, default, max |
J. Bruce Fields | 53025f5 | 2008-07-10 16:47:41 -0700 | [diff] [blame] | 570 | min: Amount of memory reserved for send buffers for TCP sockets. |
Stephen Hemminger | ef56e62 | 2006-11-09 16:37:26 -0800 | [diff] [blame] | 571 | Each TCP socket has rights to use it due to fact of its birth. |
Max Matveev | 6539fef | 2011-06-21 21:18:13 +0000 | [diff] [blame] | 572 | Default: 1 page |
Stephen Hemminger | ef56e62 | 2006-11-09 16:37:26 -0800 | [diff] [blame] | 573 | |
J. Bruce Fields | 53025f5 | 2008-07-10 16:47:41 -0700 | [diff] [blame] | 574 | default: initial size of send buffer used by TCP sockets. This |
| 575 | value overrides net.core.wmem_default used by other protocols. |
| 576 | It is usually lower than net.core.wmem_default. |
Stephen Hemminger | ef56e62 | 2006-11-09 16:37:26 -0800 | [diff] [blame] | 577 | Default: 16K |
| 578 | |
J. Bruce Fields | 53025f5 | 2008-07-10 16:47:41 -0700 | [diff] [blame] | 579 | max: Maximal amount of memory allowed for automatically tuned |
| 580 | send buffers for TCP sockets. This value does not override |
| 581 | net.core.wmem_max. Calling setsockopt() with SO_SNDBUF disables |
| 582 | automatic tuning of that socket's send buffer size, in which case |
| 583 | this value is ignored. |
| 584 | Default: between 64K and 4MB, depending on RAM size. |
Stephen Hemminger | ef56e62 | 2006-11-09 16:37:26 -0800 | [diff] [blame] | 585 | |
Eric Dumazet | c9bee3b7 | 2013-07-22 20:27:07 -0700 | [diff] [blame] | 586 | tcp_notsent_lowat - UNSIGNED INTEGER |
| 587 | A TCP socket can control the amount of unsent bytes in its write queue, |
| 588 | thanks to TCP_NOTSENT_LOWAT socket option. poll()/select()/epoll() |
| 589 | reports POLLOUT events if the amount of unsent bytes is below a per |
| 590 | socket value, and if the write queue is not full. sendmsg() will |
| 591 | also not add new buffers if the limit is hit. |
| 592 | |
| 593 | This global variable controls the amount of unsent data for |
| 594 | sockets not using TCP_NOTSENT_LOWAT. For these sockets, a change |
| 595 | to the global variable has immediate effect. |
| 596 | |
| 597 | Default: UINT_MAX (0xFFFFFFFF) |
| 598 | |
Stephen Hemminger | ef56e62 | 2006-11-09 16:37:26 -0800 | [diff] [blame] | 599 | tcp_workaround_signed_windows - BOOLEAN |
| 600 | If set, assume no receipt of a window scaling option means the |
| 601 | remote TCP is broken and treats the window as a signed quantity. |
| 602 | If unset, assume the remote TCP is not broken even if we do |
| 603 | not receive a window scaling option from them. |
| 604 | Default: 0 |
| 605 | |
Andreas Petlund | 36e31b0a | 2010-02-18 02:47:01 +0000 | [diff] [blame] | 606 | tcp_thin_linear_timeouts - BOOLEAN |
| 607 | Enable dynamic triggering of linear timeouts for thin streams. |
| 608 | If set, a check is performed upon retransmission by timeout to |
| 609 | determine if the stream is thin (less than 4 packets in flight). |
| 610 | As long as the stream is found to be thin, up to 6 linear |
| 611 | timeouts may be performed before exponential backoff mode is |
| 612 | initiated. This improves retransmission latency for |
| 613 | non-aggressive thin streams, often found to be time-dependent. |
| 614 | For more information on thin streams, see |
| 615 | Documentation/networking/tcp-thin.txt |
| 616 | Default: 0 |
| 617 | |
Andreas Petlund | 7e38017 | 2010-02-18 04:48:19 +0000 | [diff] [blame] | 618 | tcp_thin_dupack - BOOLEAN |
| 619 | Enable dynamic triggering of retransmissions after one dupACK |
| 620 | for thin streams. If set, a check is performed upon reception |
| 621 | of a dupACK to determine if the stream is thin (less than 4 |
| 622 | packets in flight). As long as the stream is found to be thin, |
| 623 | data is retransmitted on the first received dupACK. This |
| 624 | improves retransmission latency for non-aggressive thin |
| 625 | streams, often found to be time-dependent. |
| 626 | For more information on thin streams, see |
| 627 | Documentation/networking/tcp-thin.txt |
| 628 | Default: 0 |
| 629 | |
Eric Dumazet | 46d3cea | 2012-07-11 05:50:31 +0000 | [diff] [blame] | 630 | tcp_limit_output_bytes - INTEGER |
| 631 | Controls TCP Small Queue limit per tcp socket. |
| 632 | TCP bulk sender tends to increase packets in flight until it |
| 633 | gets losses notifications. With SNDBUF autotuning, this can |
| 634 | result in a large amount of packets queued in qdisc/device |
| 635 | on the local machine, hurting latency of other flows, for |
| 636 | typical pfifo_fast qdiscs. |
| 637 | tcp_limit_output_bytes limits the number of bytes on qdisc |
| 638 | or device to reduce artificial RTT/cwnd and reduce bufferbloat. |
Eric Dumazet | 46d3cea | 2012-07-11 05:50:31 +0000 | [diff] [blame] | 639 | Default: 131072 |
| 640 | |
Eric Dumazet | 282f23c | 2012-07-17 10:13:05 +0200 | [diff] [blame] | 641 | tcp_challenge_ack_limit - INTEGER |
| 642 | Limits number of Challenge ACK sent per second, as recommended |
| 643 | in RFC 5961 (Improving TCP's Robustness to Blind In-Window Attacks) |
| 644 | Default: 100 |
| 645 | |
Hideo Aoki | 95766ff | 2007-12-31 00:29:24 -0800 | [diff] [blame] | 646 | UDP variables: |
| 647 | |
| 648 | udp_mem - vector of 3 INTEGERs: min, pressure, max |
| 649 | Number of pages allowed for queueing by all UDP sockets. |
| 650 | |
| 651 | min: Below this number of pages UDP is not bothered about its |
| 652 | memory appetite. When amount of memory allocated by UDP exceeds |
| 653 | this number, UDP starts to moderate memory usage. |
| 654 | |
| 655 | pressure: This value was introduced to follow format of tcp_mem. |
| 656 | |
| 657 | max: Number of pages allowed for queueing by all UDP sockets. |
| 658 | |
| 659 | Default is calculated at boot time from amount of available memory. |
| 660 | |
| 661 | udp_rmem_min - INTEGER |
| 662 | Minimal size of receive buffer used by UDP sockets in moderation. |
| 663 | Each UDP socket is able to use the size for receiving data, even if |
| 664 | total pages of UDP sockets exceed udp_mem pressure. The unit is byte. |
Max Matveev | 6539fef | 2011-06-21 21:18:13 +0000 | [diff] [blame] | 665 | Default: 1 page |
Hideo Aoki | 95766ff | 2007-12-31 00:29:24 -0800 | [diff] [blame] | 666 | |
| 667 | udp_wmem_min - INTEGER |
| 668 | Minimal size of send buffer used by UDP sockets in moderation. |
| 669 | Each UDP socket is able to use the size for sending data, even if |
| 670 | total pages of UDP sockets exceed udp_mem pressure. The unit is byte. |
Max Matveev | 6539fef | 2011-06-21 21:18:13 +0000 | [diff] [blame] | 671 | Default: 1 page |
Hideo Aoki | 95766ff | 2007-12-31 00:29:24 -0800 | [diff] [blame] | 672 | |
Paul Moore | 8802f61 | 2006-08-03 16:45:49 -0700 | [diff] [blame] | 673 | CIPSOv4 Variables: |
| 674 | |
| 675 | cipso_cache_enable - BOOLEAN |
| 676 | If set, enable additions to and lookups from the CIPSO label mapping |
| 677 | cache. If unset, additions are ignored and lookups always result in a |
| 678 | miss. However, regardless of the setting the cache is still |
| 679 | invalidated when required when means you can safely toggle this on and |
| 680 | off and the cache will always be "safe". |
| 681 | Default: 1 |
| 682 | |
| 683 | cipso_cache_bucket_size - INTEGER |
| 684 | The CIPSO label cache consists of a fixed size hash table with each |
| 685 | hash bucket containing a number of cache entries. This variable limits |
| 686 | the number of entries in each hash bucket; the larger the value the |
| 687 | more CIPSO label mappings that can be cached. When the number of |
| 688 | entries in a given hash bucket reaches this limit adding new entries |
| 689 | causes the oldest entry in the bucket to be removed to make room. |
| 690 | Default: 10 |
| 691 | |
| 692 | cipso_rbm_optfmt - BOOLEAN |
| 693 | Enable the "Optimized Tag 1 Format" as defined in section 3.4.2.6 of |
| 694 | the CIPSO draft specification (see Documentation/netlabel for details). |
| 695 | This means that when set the CIPSO tag will be padded with empty |
| 696 | categories in order to make the packet data 32-bit aligned. |
| 697 | Default: 0 |
| 698 | |
| 699 | cipso_rbm_structvalid - BOOLEAN |
| 700 | If set, do a very strict check of the CIPSO option when |
| 701 | ip_options_compile() is called. If unset, relax the checks done during |
| 702 | ip_options_compile(). Either way is "safe" as errors are caught else |
| 703 | where in the CIPSO processing code but setting this to 0 (False) should |
| 704 | result in less work (i.e. it should be faster) but could cause problems |
| 705 | with other implementations that require strict checking. |
| 706 | Default: 0 |
| 707 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 708 | IP Variables: |
| 709 | |
| 710 | ip_local_port_range - 2 INTEGERS |
| 711 | Defines the local port range that is used by TCP and UDP to |
Jesper Dangaard Brouer | e18f5fe | 2009-02-23 04:39:04 +0000 | [diff] [blame] | 712 | choose the local port. The first number is the first, the |
Fernando Luis Vazquez Cao | 5d6bd86 | 2012-04-03 08:41:40 +0000 | [diff] [blame] | 713 | second the last local port number. The default values are |
| 714 | 32768 and 61000 respectively. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 715 | |
Amerigo Wang | e3826f1 | 2010-05-05 00:27:06 +0000 | [diff] [blame] | 716 | ip_local_reserved_ports - list of comma separated ranges |
| 717 | Specify the ports which are reserved for known third-party |
| 718 | applications. These ports will not be used by automatic port |
| 719 | assignments (e.g. when calling connect() or bind() with port |
| 720 | number 0). Explicit port allocation behavior is unchanged. |
| 721 | |
| 722 | The format used for both input and output is a comma separated |
| 723 | list of ranges (e.g. "1,2-4,10-10" for ports 1, 2, 3, 4 and |
| 724 | 10). Writing to the file will clear all previously reserved |
| 725 | ports and update the current list with the one given in the |
| 726 | input. |
| 727 | |
| 728 | Note that ip_local_port_range and ip_local_reserved_ports |
| 729 | settings are independent and both are considered by the kernel |
| 730 | when determining which ports are available for automatic port |
| 731 | assignments. |
| 732 | |
| 733 | You can reserve ports which are not in the current |
| 734 | ip_local_port_range, e.g.: |
| 735 | |
| 736 | $ cat /proc/sys/net/ipv4/ip_local_port_range |
| 737 | 32000 61000 |
| 738 | $ cat /proc/sys/net/ipv4/ip_local_reserved_ports |
| 739 | 8080,9148 |
| 740 | |
| 741 | although this is redundant. However such a setting is useful |
| 742 | if later the port range is changed to a value that will |
| 743 | include the reserved ports. |
| 744 | |
| 745 | Default: Empty |
| 746 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 747 | ip_nonlocal_bind - BOOLEAN |
| 748 | If set, allows processes to bind() to non-local IP addresses, |
| 749 | which can be quite useful - but may break some applications. |
| 750 | Default: 0 |
| 751 | |
| 752 | ip_dynaddr - BOOLEAN |
| 753 | If set non-zero, enables support for dynamic addresses. |
| 754 | If set to a non-zero value larger than 1, a kernel log |
| 755 | message will be printed when dynamic address rewriting |
| 756 | occurs. |
| 757 | Default: 0 |
| 758 | |
Cong Wang | e3d73bc | 2013-06-11 18:54:39 +0800 | [diff] [blame] | 759 | ip_early_demux - BOOLEAN |
| 760 | Optimize input packet processing down to one demux for |
| 761 | certain kinds of local sockets. Currently we only do this |
| 762 | for established TCP sockets. |
| 763 | |
| 764 | It may add an additional cost for pure routing workloads that |
| 765 | reduces overall throughput, in such case you should disable it. |
| 766 | Default: 1 |
| 767 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 768 | icmp_echo_ignore_all - BOOLEAN |
David S. Miller | 7ce31246 | 2005-10-03 16:07:30 -0700 | [diff] [blame] | 769 | If set non-zero, then the kernel will ignore all ICMP ECHO |
| 770 | requests sent to it. |
| 771 | Default: 0 |
| 772 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 773 | icmp_echo_ignore_broadcasts - BOOLEAN |
David S. Miller | 7ce31246 | 2005-10-03 16:07:30 -0700 | [diff] [blame] | 774 | If set non-zero, then the kernel will ignore all ICMP ECHO and |
| 775 | TIMESTAMP requests sent to it via broadcast/multicast. |
| 776 | Default: 1 |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 777 | |
| 778 | icmp_ratelimit - INTEGER |
| 779 | Limit the maximal rates for sending ICMP packets whose type matches |
| 780 | icmp_ratemask (see below) to specific targets. |
Stephen Hemminger | 6dbf4bc | 2008-07-01 19:29:07 -0700 | [diff] [blame] | 781 | 0 to disable any limiting, |
| 782 | otherwise the minimal space between responses in milliseconds. |
Eric Dumazet | 4cdf507 | 2014-09-19 07:38:40 -0700 | [diff] [blame] | 783 | Note that another sysctl, icmp_msgs_per_sec limits the number |
| 784 | of ICMP packets sent on all targets. |
Stephen Hemminger | 6dbf4bc | 2008-07-01 19:29:07 -0700 | [diff] [blame] | 785 | Default: 1000 |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 786 | |
Eric Dumazet | 4cdf507 | 2014-09-19 07:38:40 -0700 | [diff] [blame] | 787 | icmp_msgs_per_sec - INTEGER |
| 788 | Limit maximal number of ICMP packets sent per second from this host. |
| 789 | Only messages whose type matches icmp_ratemask (see below) are |
| 790 | controlled by this limit. |
| 791 | Default: 1000 |
| 792 | |
| 793 | icmp_msgs_burst - INTEGER |
| 794 | icmp_msgs_per_sec controls number of ICMP packets sent per second, |
| 795 | while icmp_msgs_burst controls the burst size of these packets. |
| 796 | Default: 50 |
| 797 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 798 | icmp_ratemask - INTEGER |
| 799 | Mask made of ICMP types for which rates are being limited. |
| 800 | Significant bits: IHGFEDCBA9876543210 |
| 801 | Default mask: 0000001100000011000 (6168) |
| 802 | |
| 803 | Bit definitions (see include/linux/icmp.h): |
| 804 | 0 Echo Reply |
| 805 | 3 Destination Unreachable * |
| 806 | 4 Source Quench * |
| 807 | 5 Redirect |
| 808 | 8 Echo Request |
| 809 | B Time Exceeded * |
| 810 | C Parameter Problem * |
| 811 | D Timestamp Request |
| 812 | E Timestamp Reply |
| 813 | F Info Request |
| 814 | G Info Reply |
| 815 | H Address Mask Request |
| 816 | I Address Mask Reply |
| 817 | |
| 818 | * These are rate limited by default (see default mask above) |
| 819 | |
| 820 | icmp_ignore_bogus_error_responses - BOOLEAN |
| 821 | Some routers violate RFC1122 by sending bogus responses to broadcast |
| 822 | frames. Such violations are normally logged via a kernel warning. |
| 823 | If this is set to TRUE, the kernel will not give such warnings, which |
| 824 | will avoid log file clutter. |
Rami Rosen | e8b265e | 2013-06-07 20:16:19 +0000 | [diff] [blame] | 825 | Default: 1 |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 826 | |
Horms | 95f7daf | 2006-02-02 17:02:25 -0800 | [diff] [blame] | 827 | icmp_errors_use_inbound_ifaddr - BOOLEAN |
| 828 | |
| 829 | If zero, icmp error messages are sent with the primary address of |
| 830 | the exiting interface. |
Jesper Dangaard Brouer | e18f5fe | 2009-02-23 04:39:04 +0000 | [diff] [blame] | 831 | |
Horms | 95f7daf | 2006-02-02 17:02:25 -0800 | [diff] [blame] | 832 | If non-zero, the message will be sent with the primary address of |
| 833 | the interface that received the packet that caused the icmp error. |
| 834 | This is the behaviour network many administrators will expect from |
| 835 | a router. And it can make debugging complicated network layouts |
Jesper Dangaard Brouer | e18f5fe | 2009-02-23 04:39:04 +0000 | [diff] [blame] | 836 | much easier. |
Horms | 95f7daf | 2006-02-02 17:02:25 -0800 | [diff] [blame] | 837 | |
| 838 | Note that if no primary address exists for the interface selected, |
| 839 | then the primary address of the first non-loopback interface that |
Matt LaPlante | d6bc8ac | 2006-10-03 22:54:15 +0200 | [diff] [blame] | 840 | has one will be used regardless of this setting. |
Horms | 95f7daf | 2006-02-02 17:02:25 -0800 | [diff] [blame] | 841 | |
| 842 | Default: 0 |
| 843 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 844 | igmp_max_memberships - INTEGER |
| 845 | Change the maximum number of multicast groups we can subscribe to. |
| 846 | Default: 20 |
| 847 | |
Jeremy Eder | d67ef35 | 2010-11-15 05:41:31 +0000 | [diff] [blame] | 848 | Theoretical maximum value is bounded by having to send a membership |
| 849 | report in a single datagram (i.e. the report can't span multiple |
| 850 | datagrams, or risk confusing the switch and leaving groups you don't |
| 851 | intend to). |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 852 | |
Jeremy Eder | d67ef35 | 2010-11-15 05:41:31 +0000 | [diff] [blame] | 853 | The number of supported groups 'M' is bounded by the number of group |
| 854 | report entries you can fit into a single datagram of 65535 bytes. |
| 855 | |
| 856 | M = 65536-sizeof (ip header)/(sizeof(Group record)) |
| 857 | |
| 858 | Group records are variable length, with a minimum of 12 bytes. |
| 859 | So net.ipv4.igmp_max_memberships should not be set higher than: |
| 860 | |
| 861 | (65536-24) / 12 = 5459 |
| 862 | |
| 863 | The value 5459 assumes no IP header options, so in practice |
| 864 | this number may be lower. |
| 865 | |
| 866 | conf/interface/* changes special settings per interface (where |
| 867 | "interface" is the name of your network interface) |
| 868 | |
| 869 | conf/all/* is special, changes the settings for all interfaces |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 870 | |
Hannes Frederic Sowa | a9fe8e2 | 2014-09-02 15:49:26 +0200 | [diff] [blame] | 871 | igmp_qrv - INTEGER |
| 872 | Controls the IGMP query robustness variable (see RFC2236 8.1). |
| 873 | Default: 2 (as specified by RFC2236 8.1) |
| 874 | Minimum: 1 (as specified by RFC6636 4.5) |
| 875 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 876 | log_martians - BOOLEAN |
| 877 | Log packets with impossible addresses to kernel log. |
| 878 | log_martians for the interface will be enabled if at least one of |
| 879 | conf/{all,interface}/log_martians is set to TRUE, |
| 880 | it will be disabled otherwise |
| 881 | |
| 882 | accept_redirects - BOOLEAN |
| 883 | Accept ICMP redirect messages. |
| 884 | accept_redirects for the interface will be enabled if: |
Jesper Dangaard Brouer | e18f5fe | 2009-02-23 04:39:04 +0000 | [diff] [blame] | 885 | - both conf/{all,interface}/accept_redirects are TRUE in the case |
| 886 | forwarding for the interface is enabled |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 887 | or |
Jesper Dangaard Brouer | e18f5fe | 2009-02-23 04:39:04 +0000 | [diff] [blame] | 888 | - at least one of conf/{all,interface}/accept_redirects is TRUE in the |
| 889 | case forwarding for the interface is disabled |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 890 | accept_redirects for the interface will be disabled otherwise |
| 891 | default TRUE (host) |
| 892 | FALSE (router) |
| 893 | |
| 894 | forwarding - BOOLEAN |
| 895 | Enable IP forwarding on this interface. |
| 896 | |
| 897 | mc_forwarding - BOOLEAN |
| 898 | Do multicast routing. The kernel needs to be compiled with CONFIG_MROUTE |
| 899 | and a multicast routing daemon is required. |
Jesper Dangaard Brouer | e18f5fe | 2009-02-23 04:39:04 +0000 | [diff] [blame] | 900 | conf/all/mc_forwarding must also be set to TRUE to enable multicast |
| 901 | routing for the interface |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 902 | |
| 903 | medium_id - INTEGER |
| 904 | Integer value used to differentiate the devices by the medium they |
| 905 | are attached to. Two devices can have different id values when |
| 906 | the broadcast packets are received only on one of them. |
| 907 | The default value 0 means that the device is the only interface |
| 908 | to its medium, value of -1 means that medium is not known. |
Jesper Dangaard Brouer | e18f5fe | 2009-02-23 04:39:04 +0000 | [diff] [blame] | 909 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 910 | Currently, it is used to change the proxy_arp behavior: |
| 911 | the proxy_arp feature is enabled for packets forwarded between |
| 912 | two devices attached to different media. |
| 913 | |
| 914 | proxy_arp - BOOLEAN |
| 915 | Do proxy arp. |
| 916 | proxy_arp for the interface will be enabled if at least one of |
| 917 | conf/{all,interface}/proxy_arp is set to TRUE, |
| 918 | it will be disabled otherwise |
| 919 | |
Jesper Dangaard Brouer | 6532414 | 2010-01-05 05:50:47 +0000 | [diff] [blame] | 920 | proxy_arp_pvlan - BOOLEAN |
| 921 | Private VLAN proxy arp. |
| 922 | Basically allow proxy arp replies back to the same interface |
| 923 | (from which the ARP request/solicitation was received). |
| 924 | |
| 925 | This is done to support (ethernet) switch features, like RFC |
| 926 | 3069, where the individual ports are NOT allowed to |
| 927 | communicate with each other, but they are allowed to talk to |
| 928 | the upstream router. As described in RFC 3069, it is possible |
| 929 | to allow these hosts to communicate through the upstream |
| 930 | router by proxy_arp'ing. Don't need to be used together with |
| 931 | proxy_arp. |
| 932 | |
| 933 | This technology is known by different names: |
| 934 | In RFC 3069 it is called VLAN Aggregation. |
| 935 | Cisco and Allied Telesyn call it Private VLAN. |
| 936 | Hewlett-Packard call it Source-Port filtering or port-isolation. |
| 937 | Ericsson call it MAC-Forced Forwarding (RFC Draft). |
| 938 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 939 | shared_media - BOOLEAN |
| 940 | Send(router) or accept(host) RFC1620 shared media redirects. |
| 941 | Overrides ip_secure_redirects. |
| 942 | shared_media for the interface will be enabled if at least one of |
| 943 | conf/{all,interface}/shared_media is set to TRUE, |
| 944 | it will be disabled otherwise |
| 945 | default TRUE |
| 946 | |
| 947 | secure_redirects - BOOLEAN |
| 948 | Accept ICMP redirect messages only for gateways, |
| 949 | listed in default gateway list. |
| 950 | secure_redirects for the interface will be enabled if at least one of |
| 951 | conf/{all,interface}/secure_redirects is set to TRUE, |
| 952 | it will be disabled otherwise |
| 953 | default TRUE |
| 954 | |
| 955 | send_redirects - BOOLEAN |
| 956 | Send redirects, if router. |
| 957 | send_redirects for the interface will be enabled if at least one of |
| 958 | conf/{all,interface}/send_redirects is set to TRUE, |
| 959 | it will be disabled otherwise |
| 960 | Default: TRUE |
| 961 | |
| 962 | bootp_relay - BOOLEAN |
| 963 | Accept packets with source address 0.b.c.d destined |
| 964 | not to this host as local ones. It is supposed, that |
| 965 | BOOTP relay daemon will catch and forward such packets. |
| 966 | conf/all/bootp_relay must also be set to TRUE to enable BOOTP relay |
| 967 | for the interface |
| 968 | default FALSE |
| 969 | Not Implemented Yet. |
| 970 | |
| 971 | accept_source_route - BOOLEAN |
| 972 | Accept packets with SRR option. |
| 973 | conf/all/accept_source_route must also be set to TRUE to accept packets |
| 974 | with SRR option on the interface |
| 975 | default TRUE (router) |
| 976 | FALSE (host) |
| 977 | |
Patrick McHardy | 8153a10 | 2009-12-03 01:25:58 +0000 | [diff] [blame] | 978 | accept_local - BOOLEAN |
Sébastien Barré | 72b126a | 2014-09-10 18:20:23 +0200 | [diff] [blame] | 979 | Accept packets with local source addresses. In combination with |
| 980 | suitable routing, this can be used to direct packets between two |
| 981 | local interfaces over the wire and have them accepted properly. |
Patrick McHardy | 8153a10 | 2009-12-03 01:25:58 +0000 | [diff] [blame] | 982 | default FALSE |
| 983 | |
Thomas Graf | d0daebc3 | 2012-06-12 00:44:01 +0000 | [diff] [blame] | 984 | route_localnet - BOOLEAN |
| 985 | Do not consider loopback addresses as martian source or destination |
| 986 | while routing. This enables the use of 127/8 for local routing purposes. |
| 987 | default FALSE |
| 988 | |
Stephen Hemminger | c1cf842 | 2009-02-20 08:25:36 +0000 | [diff] [blame] | 989 | rp_filter - INTEGER |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 990 | 0 - No source validation. |
Stephen Hemminger | c1cf842 | 2009-02-20 08:25:36 +0000 | [diff] [blame] | 991 | 1 - Strict mode as defined in RFC3704 Strict Reverse Path |
| 992 | Each incoming packet is tested against the FIB and if the interface |
| 993 | is not the best reverse path the packet check will fail. |
| 994 | By default failed packets are discarded. |
| 995 | 2 - Loose mode as defined in RFC3704 Loose Reverse Path |
| 996 | Each incoming packet's source address is also tested against the FIB |
| 997 | and if the source address is not reachable via any interface |
| 998 | the packet check will fail. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 999 | |
Jesper Dangaard Brouer | e18f5fe | 2009-02-23 04:39:04 +0000 | [diff] [blame] | 1000 | Current recommended practice in RFC3704 is to enable strict mode |
Jesper Dangaard Brouer | bf869c3 | 2009-02-23 04:37:55 +0000 | [diff] [blame] | 1001 | to prevent IP spoofing from DDos attacks. If using asymmetric routing |
Jesper Dangaard Brouer | e18f5fe | 2009-02-23 04:39:04 +0000 | [diff] [blame] | 1002 | or other complicated routing, then loose mode is recommended. |
Stephen Hemminger | c1cf842 | 2009-02-20 08:25:36 +0000 | [diff] [blame] | 1003 | |
Shan Wei | 1f5865e | 2009-12-02 15:39:04 -0800 | [diff] [blame] | 1004 | The max value from conf/{all,interface}/rp_filter is used |
| 1005 | when doing source validation on the {interface}. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1006 | |
| 1007 | Default value is 0. Note that some distributions enable it |
| 1008 | in startup scripts. |
| 1009 | |
| 1010 | arp_filter - BOOLEAN |
| 1011 | 1 - Allows you to have multiple network interfaces on the same |
| 1012 | subnet, and have the ARPs for each interface be answered |
| 1013 | based on whether or not the kernel would route a packet from |
| 1014 | the ARP'd IP out that interface (therefore you must use source |
| 1015 | based routing for this to work). In other words it allows control |
| 1016 | of which cards (usually 1) will respond to an arp request. |
| 1017 | |
| 1018 | 0 - (default) The kernel can respond to arp requests with addresses |
| 1019 | from other interfaces. This may seem wrong but it usually makes |
| 1020 | sense, because it increases the chance of successful communication. |
| 1021 | IP addresses are owned by the complete host on Linux, not by |
| 1022 | particular interfaces. Only for more complex setups like load- |
| 1023 | balancing, does this behaviour cause problems. |
| 1024 | |
| 1025 | arp_filter for the interface will be enabled if at least one of |
| 1026 | conf/{all,interface}/arp_filter is set to TRUE, |
| 1027 | it will be disabled otherwise |
| 1028 | |
| 1029 | arp_announce - INTEGER |
| 1030 | Define different restriction levels for announcing the local |
| 1031 | source IP address from IP packets in ARP requests sent on |
| 1032 | interface: |
| 1033 | 0 - (default) Use any local address, configured on any interface |
| 1034 | 1 - Try to avoid local addresses that are not in the target's |
| 1035 | subnet for this interface. This mode is useful when target |
| 1036 | hosts reachable via this interface require the source IP |
| 1037 | address in ARP requests to be part of their logical network |
| 1038 | configured on the receiving interface. When we generate the |
| 1039 | request we will check all our subnets that include the |
| 1040 | target IP and will preserve the source address if it is from |
| 1041 | such subnet. If there is no such subnet we select source |
| 1042 | address according to the rules for level 2. |
| 1043 | 2 - Always use the best local address for this target. |
| 1044 | In this mode we ignore the source address in the IP packet |
| 1045 | and try to select local address that we prefer for talks with |
| 1046 | the target host. Such local address is selected by looking |
| 1047 | for primary IP addresses on all our subnets on the outgoing |
| 1048 | interface that include the target IP address. If no suitable |
| 1049 | local address is found we select the first local address |
| 1050 | we have on the outgoing interface or on all other interfaces, |
| 1051 | with the hope we will receive reply for our request and |
| 1052 | even sometimes no matter the source IP address we announce. |
| 1053 | |
| 1054 | The max value from conf/{all,interface}/arp_announce is used. |
| 1055 | |
| 1056 | Increasing the restriction level gives more chance for |
| 1057 | receiving answer from the resolved target while decreasing |
| 1058 | the level announces more valid sender's information. |
| 1059 | |
| 1060 | arp_ignore - INTEGER |
| 1061 | Define different modes for sending replies in response to |
| 1062 | received ARP requests that resolve local target IP addresses: |
| 1063 | 0 - (default): reply for any local target IP address, configured |
| 1064 | on any interface |
| 1065 | 1 - reply only if the target IP address is local address |
| 1066 | configured on the incoming interface |
| 1067 | 2 - reply only if the target IP address is local address |
| 1068 | configured on the incoming interface and both with the |
| 1069 | sender's IP address are part from same subnet on this interface |
| 1070 | 3 - do not reply for local addresses configured with scope host, |
| 1071 | only resolutions for global and link addresses are replied |
| 1072 | 4-7 - reserved |
| 1073 | 8 - do not reply for all local addresses |
| 1074 | |
| 1075 | The max value from conf/{all,interface}/arp_ignore is used |
| 1076 | when ARP request is received on the {interface} |
| 1077 | |
Stephen Hemminger | eefef1c | 2009-02-01 01:04:33 -0800 | [diff] [blame] | 1078 | arp_notify - BOOLEAN |
| 1079 | Define mode for notification of address and device changes. |
| 1080 | 0 - (default): do nothing |
Ian Campbell | 3f8dc23 | 2010-05-26 00:09:41 +0000 | [diff] [blame] | 1081 | 1 - Generate gratuitous arp requests when device is brought up |
Stephen Hemminger | eefef1c | 2009-02-01 01:04:33 -0800 | [diff] [blame] | 1082 | or hardware address changes. |
| 1083 | |
Neil Horman | c1b1bce | 2006-03-20 22:40:03 -0800 | [diff] [blame] | 1084 | arp_accept - BOOLEAN |
Octavian Purdila | 6d95518 | 2010-01-18 12:58:44 +0000 | [diff] [blame] | 1085 | Define behavior for gratuitous ARP frames who's IP is not |
| 1086 | already present in the ARP table: |
| 1087 | 0 - don't create new entries in the ARP table |
| 1088 | 1 - create new entries in the ARP table |
| 1089 | |
| 1090 | Both replies and requests type gratuitous arp will trigger the |
| 1091 | ARP table to be updated, if this setting is on. |
| 1092 | |
| 1093 | If the ARP table already contains the IP address of the |
| 1094 | gratuitous arp frame, the arp table will be updated regardless |
| 1095 | if this setting is on or off. |
| 1096 | |
Neil Horman | c1b1bce | 2006-03-20 22:40:03 -0800 | [diff] [blame] | 1097 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1098 | app_solicit - INTEGER |
| 1099 | The maximum number of probes to send to the user space ARP daemon |
| 1100 | via netlink before dropping back to multicast probes (see |
| 1101 | mcast_solicit). Defaults to 0. |
| 1102 | |
| 1103 | disable_policy - BOOLEAN |
| 1104 | Disable IPSEC policy (SPD) for this interface |
| 1105 | |
| 1106 | disable_xfrm - BOOLEAN |
| 1107 | Disable IPSEC encryption on this interface, whatever the policy |
| 1108 | |
Hannes Frederic Sowa | fc4eba5 | 2013-08-14 01:03:46 +0200 | [diff] [blame] | 1109 | igmpv2_unsolicited_report_interval - INTEGER |
| 1110 | The interval in milliseconds in which the next unsolicited |
| 1111 | IGMPv1 or IGMPv2 report retransmit will take place. |
| 1112 | Default: 10000 (10 seconds) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1113 | |
Hannes Frederic Sowa | fc4eba5 | 2013-08-14 01:03:46 +0200 | [diff] [blame] | 1114 | igmpv3_unsolicited_report_interval - INTEGER |
| 1115 | The interval in milliseconds in which the next unsolicited |
| 1116 | IGMPv3 report retransmit will take place. |
| 1117 | Default: 1000 (1 seconds) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1118 | |
Martin Schwenke | d922e1c | 2014-01-28 15:26:42 +1100 | [diff] [blame] | 1119 | promote_secondaries - BOOLEAN |
| 1120 | When a primary IP address is removed from this interface |
| 1121 | promote a corresponding secondary IP address instead of |
| 1122 | removing all the corresponding secondary IP addresses. |
| 1123 | |
| 1124 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1125 | tag - INTEGER |
| 1126 | Allows you to write a number, which can be used as required. |
| 1127 | Default value is 0. |
| 1128 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1129 | Alexey Kuznetsov. |
| 1130 | kuznet@ms2.inr.ac.ru |
| 1131 | |
| 1132 | Updated by: |
| 1133 | Andi Kleen |
| 1134 | ak@muc.de |
| 1135 | Nicolas Delon |
| 1136 | delon.nicolas@wanadoo.fr |
| 1137 | |
| 1138 | |
| 1139 | |
| 1140 | |
| 1141 | /proc/sys/net/ipv6/* Variables: |
| 1142 | |
| 1143 | IPv6 has no global variables such as tcp_*. tcp_* settings under ipv4/ also |
| 1144 | apply to IPv6 [XXX?]. |
| 1145 | |
| 1146 | bindv6only - BOOLEAN |
| 1147 | Default value for IPV6_V6ONLY socket option, |
Jesper Dangaard Brouer | e18f5fe | 2009-02-23 04:39:04 +0000 | [diff] [blame] | 1148 | which restricts use of the IPv6 socket to IPv6 communication |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1149 | only. |
| 1150 | TRUE: disable IPv4-mapped address feature |
| 1151 | FALSE: enable IPv4-mapped address feature |
| 1152 | |
Geoffrey Thomas | d5c073ca | 2011-08-22 11:28:57 -0700 | [diff] [blame] | 1153 | Default: FALSE (as specified in RFC3493) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1154 | |
Florent Fourcot | 6444f72 | 2014-01-17 17:15:05 +0100 | [diff] [blame] | 1155 | flowlabel_consistency - BOOLEAN |
| 1156 | Protect the consistency (and unicity) of flow label. |
| 1157 | You have to disable it to use IPV6_FL_F_REFLECT flag on the |
| 1158 | flow label manager. |
| 1159 | TRUE: enabled |
| 1160 | FALSE: disabled |
| 1161 | Default: TRUE |
| 1162 | |
Tom Herbert | cb1ce2e | 2014-07-01 21:33:10 -0700 | [diff] [blame] | 1163 | auto_flowlabels - BOOLEAN |
| 1164 | Automatically generate flow labels based based on a flow hash |
| 1165 | of the packet. This allows intermediate devices, such as routers, |
| 1166 | to idenfify packet flows for mechanisms like Equal Cost Multipath |
| 1167 | Routing (see RFC 6438). |
| 1168 | TRUE: enabled |
| 1169 | FALSE: disabled |
| 1170 | Default: false |
| 1171 | |
FX Le Bail | 509aba3 | 2014-01-07 14:57:27 +0100 | [diff] [blame] | 1172 | anycast_src_echo_reply - BOOLEAN |
| 1173 | Controls the use of anycast addresses as source addresses for ICMPv6 |
| 1174 | echo reply |
| 1175 | TRUE: enabled |
| 1176 | FALSE: disabled |
| 1177 | Default: FALSE |
| 1178 | |
Hannes Frederic Sowa | 2f71193 | 2014-09-02 15:49:25 +0200 | [diff] [blame] | 1179 | mld_qrv - INTEGER |
| 1180 | Controls the MLD query robustness variable (see RFC3810 9.1). |
| 1181 | Default: 2 (as specified by RFC3810 9.1) |
| 1182 | Minimum: 1 (as specified by RFC6636 4.5) |
| 1183 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1184 | IPv6 Fragmentation: |
| 1185 | |
| 1186 | ip6frag_high_thresh - INTEGER |
Jesper Dangaard Brouer | e18f5fe | 2009-02-23 04:39:04 +0000 | [diff] [blame] | 1187 | Maximum memory used to reassemble IPv6 fragments. When |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1188 | ip6frag_high_thresh bytes of memory is allocated for this purpose, |
| 1189 | the fragment handler will toss packets until ip6frag_low_thresh |
| 1190 | is reached. |
Jesper Dangaard Brouer | e18f5fe | 2009-02-23 04:39:04 +0000 | [diff] [blame] | 1191 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1192 | ip6frag_low_thresh - INTEGER |
Jesper Dangaard Brouer | e18f5fe | 2009-02-23 04:39:04 +0000 | [diff] [blame] | 1193 | See ip6frag_high_thresh |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1194 | |
| 1195 | ip6frag_time - INTEGER |
| 1196 | Time in seconds to keep an IPv6 fragment in memory. |
| 1197 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1198 | conf/default/*: |
| 1199 | Change the interface-specific default settings. |
| 1200 | |
| 1201 | |
| 1202 | conf/all/*: |
Jesper Dangaard Brouer | e18f5fe | 2009-02-23 04:39:04 +0000 | [diff] [blame] | 1203 | Change all the interface-specific settings. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1204 | |
| 1205 | [XXX: Other special features than forwarding?] |
| 1206 | |
| 1207 | conf/all/forwarding - BOOLEAN |
Jesper Dangaard Brouer | e18f5fe | 2009-02-23 04:39:04 +0000 | [diff] [blame] | 1208 | Enable global IPv6 forwarding between all interfaces. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1209 | |
Jesper Dangaard Brouer | e18f5fe | 2009-02-23 04:39:04 +0000 | [diff] [blame] | 1210 | IPv4 and IPv6 work differently here; e.g. netfilter must be used |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1211 | to control which interfaces may forward packets and which not. |
| 1212 | |
Jesper Dangaard Brouer | e18f5fe | 2009-02-23 04:39:04 +0000 | [diff] [blame] | 1213 | This also sets all interfaces' Host/Router setting |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1214 | 'forwarding' to the specified value. See below for details. |
| 1215 | |
| 1216 | This referred to as global forwarding. |
| 1217 | |
YOSHIFUJI Hideaki | fbea49e | 2006-09-22 14:43:49 -0700 | [diff] [blame] | 1218 | proxy_ndp - BOOLEAN |
| 1219 | Do proxy ndp. |
| 1220 | |
Loganaden Velvindron | 219b5f2 | 2014-11-04 03:02:49 -0800 | [diff] [blame] | 1221 | fwmark_reflect - BOOLEAN |
| 1222 | Controls the fwmark of kernel-generated IPv6 reply packets that are not |
| 1223 | associated with a socket for example, TCP RSTs or ICMPv6 echo replies). |
| 1224 | If unset, these packets have a fwmark of zero. If set, they have the |
| 1225 | fwmark of the packet they are replying to. |
| 1226 | Default: 0 |
| 1227 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1228 | conf/interface/*: |
| 1229 | Change special settings per interface. |
| 1230 | |
Jesper Dangaard Brouer | e18f5fe | 2009-02-23 04:39:04 +0000 | [diff] [blame] | 1231 | The functional behaviour for certain settings is different |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1232 | depending on whether local forwarding is enabled or not. |
| 1233 | |
Roy.Li | 605b91c | 2011-09-28 19:51:54 +0000 | [diff] [blame] | 1234 | accept_ra - INTEGER |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1235 | Accept Router Advertisements; autoconfigure using them. |
Jesper Dangaard Brouer | e18f5fe | 2009-02-23 04:39:04 +0000 | [diff] [blame] | 1236 | |
Tore Anderson | 026359b | 2011-08-28 23:47:33 +0000 | [diff] [blame] | 1237 | It also determines whether or not to transmit Router |
| 1238 | Solicitations. If and only if the functional setting is to |
| 1239 | accept Router Advertisements, Router Solicitations will be |
| 1240 | transmitted. |
| 1241 | |
Thomas Graf | ae8abfa | 2010-09-03 05:47:30 +0000 | [diff] [blame] | 1242 | Possible values are: |
| 1243 | 0 Do not accept Router Advertisements. |
| 1244 | 1 Accept Router Advertisements if forwarding is disabled. |
| 1245 | 2 Overrule forwarding behaviour. Accept Router Advertisements |
| 1246 | even if forwarding is enabled. |
| 1247 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1248 | Functional default: enabled if local forwarding is disabled. |
| 1249 | disabled if local forwarding is enabled. |
| 1250 | |
YOSHIFUJI Hideaki | 65f5c7c | 2006-03-20 16:55:08 -0800 | [diff] [blame] | 1251 | accept_ra_defrtr - BOOLEAN |
| 1252 | Learn default router in Router Advertisement. |
| 1253 | |
| 1254 | Functional default: enabled if accept_ra is enabled. |
| 1255 | disabled if accept_ra is disabled. |
| 1256 | |
Ben Greear | d933319 | 2014-06-25 14:44:53 -0700 | [diff] [blame] | 1257 | accept_ra_from_local - BOOLEAN |
| 1258 | Accept RA with source-address that is found on local machine |
| 1259 | if the RA is otherwise proper and able to be accepted. |
| 1260 | Default is to NOT accept these as it may be an un-intended |
| 1261 | network loop. |
| 1262 | |
| 1263 | Functional default: |
| 1264 | enabled if accept_ra_from_local is enabled |
| 1265 | on a specific interface. |
| 1266 | disabled if accept_ra_from_local is disabled |
| 1267 | on a specific interface. |
| 1268 | |
YOSHIFUJI Hideaki | c4fd30e | 2006-03-20 16:55:26 -0800 | [diff] [blame] | 1269 | accept_ra_pinfo - BOOLEAN |
Matt LaPlante | 2fe0ae7 | 2006-10-03 22:50:39 +0200 | [diff] [blame] | 1270 | Learn Prefix Information in Router Advertisement. |
YOSHIFUJI Hideaki | c4fd30e | 2006-03-20 16:55:26 -0800 | [diff] [blame] | 1271 | |
| 1272 | Functional default: enabled if accept_ra is enabled. |
| 1273 | disabled if accept_ra is disabled. |
| 1274 | |
YOSHIFUJI Hideaki | 09c884d | 2006-03-20 17:07:03 -0800 | [diff] [blame] | 1275 | accept_ra_rt_info_max_plen - INTEGER |
| 1276 | Maximum prefix length of Route Information in RA. |
| 1277 | |
| 1278 | Route Information w/ prefix larger than or equal to this |
| 1279 | variable shall be ignored. |
| 1280 | |
| 1281 | Functional default: 0 if accept_ra_rtr_pref is enabled. |
| 1282 | -1 if accept_ra_rtr_pref is disabled. |
| 1283 | |
YOSHIFUJI Hideaki | 930d6ff | 2006-03-20 17:05:30 -0800 | [diff] [blame] | 1284 | accept_ra_rtr_pref - BOOLEAN |
| 1285 | Accept Router Preference in RA. |
| 1286 | |
| 1287 | Functional default: enabled if accept_ra is enabled. |
| 1288 | disabled if accept_ra is disabled. |
| 1289 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1290 | accept_redirects - BOOLEAN |
| 1291 | Accept Redirects. |
| 1292 | |
| 1293 | Functional default: enabled if local forwarding is disabled. |
| 1294 | disabled if local forwarding is enabled. |
| 1295 | |
YOSHIFUJI Hideaki | 0bcbc92 | 2007-04-24 14:58:30 -0700 | [diff] [blame] | 1296 | accept_source_route - INTEGER |
| 1297 | Accept source routing (routing extension header). |
| 1298 | |
YOSHIFUJI Hideaki | bb4dbf9 | 2007-07-10 22:55:49 -0700 | [diff] [blame] | 1299 | >= 0: Accept only routing header type 2. |
YOSHIFUJI Hideaki | 0bcbc92 | 2007-04-24 14:58:30 -0700 | [diff] [blame] | 1300 | < 0: Do not accept routing header. |
| 1301 | |
| 1302 | Default: 0 |
| 1303 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1304 | autoconf - BOOLEAN |
Jesper Dangaard Brouer | e18f5fe | 2009-02-23 04:39:04 +0000 | [diff] [blame] | 1305 | Autoconfigure addresses using Prefix Information in Router |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1306 | Advertisements. |
| 1307 | |
YOSHIFUJI Hideaki | c4fd30e | 2006-03-20 16:55:26 -0800 | [diff] [blame] | 1308 | Functional default: enabled if accept_ra_pinfo is enabled. |
| 1309 | disabled if accept_ra_pinfo is disabled. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1310 | |
| 1311 | dad_transmits - INTEGER |
| 1312 | The amount of Duplicate Address Detection probes to send. |
| 1313 | Default: 1 |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1314 | |
Roy.Li | 605b91c | 2011-09-28 19:51:54 +0000 | [diff] [blame] | 1315 | forwarding - INTEGER |
Jesper Dangaard Brouer | e18f5fe | 2009-02-23 04:39:04 +0000 | [diff] [blame] | 1316 | Configure interface-specific Host/Router behaviour. |
| 1317 | |
| 1318 | Note: It is recommended to have the same setting on all |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1319 | interfaces; mixed router/host scenarios are rather uncommon. |
| 1320 | |
Thomas Graf | ae8abfa | 2010-09-03 05:47:30 +0000 | [diff] [blame] | 1321 | Possible values are: |
| 1322 | 0 Forwarding disabled |
| 1323 | 1 Forwarding enabled |
Thomas Graf | ae8abfa | 2010-09-03 05:47:30 +0000 | [diff] [blame] | 1324 | |
| 1325 | FALSE (0): |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1326 | |
| 1327 | By default, Host behaviour is assumed. This means: |
| 1328 | |
| 1329 | 1. IsRouter flag is not set in Neighbour Advertisements. |
Tore Anderson | 026359b | 2011-08-28 23:47:33 +0000 | [diff] [blame] | 1330 | 2. If accept_ra is TRUE (default), transmit Router |
| 1331 | Solicitations. |
Jesper Dangaard Brouer | e18f5fe | 2009-02-23 04:39:04 +0000 | [diff] [blame] | 1332 | 3. If accept_ra is TRUE (default), accept Router |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1333 | Advertisements (and do autoconfiguration). |
| 1334 | 4. If accept_redirects is TRUE (default), accept Redirects. |
| 1335 | |
Thomas Graf | ae8abfa | 2010-09-03 05:47:30 +0000 | [diff] [blame] | 1336 | TRUE (1): |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1337 | |
Jesper Dangaard Brouer | e18f5fe | 2009-02-23 04:39:04 +0000 | [diff] [blame] | 1338 | If local forwarding is enabled, Router behaviour is assumed. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1339 | This means exactly the reverse from the above: |
| 1340 | |
| 1341 | 1. IsRouter flag is set in Neighbour Advertisements. |
Tore Anderson | 026359b | 2011-08-28 23:47:33 +0000 | [diff] [blame] | 1342 | 2. Router Solicitations are not sent unless accept_ra is 2. |
Thomas Graf | ae8abfa | 2010-09-03 05:47:30 +0000 | [diff] [blame] | 1343 | 3. Router Advertisements are ignored unless accept_ra is 2. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1344 | 4. Redirects are ignored. |
| 1345 | |
Thomas Graf | ae8abfa | 2010-09-03 05:47:30 +0000 | [diff] [blame] | 1346 | Default: 0 (disabled) if global forwarding is disabled (default), |
| 1347 | otherwise 1 (enabled). |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1348 | |
| 1349 | hop_limit - INTEGER |
| 1350 | Default Hop Limit to set. |
| 1351 | Default: 64 |
| 1352 | |
| 1353 | mtu - INTEGER |
| 1354 | Default Maximum Transfer Unit |
| 1355 | Default: 1280 (IPv6 required minimum) |
| 1356 | |
YOSHIFUJI Hideaki | 52e1635 | 2006-03-20 17:05:47 -0800 | [diff] [blame] | 1357 | router_probe_interval - INTEGER |
| 1358 | Minimum interval (in seconds) between Router Probing described |
| 1359 | in RFC4191. |
| 1360 | |
| 1361 | Default: 60 |
| 1362 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1363 | router_solicitation_delay - INTEGER |
| 1364 | Number of seconds to wait after interface is brought up |
| 1365 | before sending Router Solicitations. |
| 1366 | Default: 1 |
| 1367 | |
| 1368 | router_solicitation_interval - INTEGER |
| 1369 | Number of seconds to wait between Router Solicitations. |
| 1370 | Default: 4 |
| 1371 | |
| 1372 | router_solicitations - INTEGER |
Jesper Dangaard Brouer | e18f5fe | 2009-02-23 04:39:04 +0000 | [diff] [blame] | 1373 | Number of Router Solicitations to send until assuming no |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1374 | routers are present. |
| 1375 | Default: 3 |
| 1376 | |
| 1377 | use_tempaddr - INTEGER |
| 1378 | Preference for Privacy Extensions (RFC3041). |
| 1379 | <= 0 : disable Privacy Extensions |
| 1380 | == 1 : enable Privacy Extensions, but prefer public |
| 1381 | addresses over temporary addresses. |
| 1382 | > 1 : enable Privacy Extensions and prefer temporary |
| 1383 | addresses over public addresses. |
| 1384 | Default: 0 (for most devices) |
| 1385 | -1 (for point-to-point devices and loopback devices) |
| 1386 | |
| 1387 | temp_valid_lft - INTEGER |
| 1388 | valid lifetime (in seconds) for temporary addresses. |
| 1389 | Default: 604800 (7 days) |
| 1390 | |
| 1391 | temp_prefered_lft - INTEGER |
| 1392 | Preferred lifetime (in seconds) for temporary addresses. |
| 1393 | Default: 86400 (1 day) |
| 1394 | |
| 1395 | max_desync_factor - INTEGER |
| 1396 | Maximum value for DESYNC_FACTOR, which is a random value |
Jesper Dangaard Brouer | e18f5fe | 2009-02-23 04:39:04 +0000 | [diff] [blame] | 1397 | that ensures that clients don't synchronize with each |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1398 | other and generate new addresses at exactly the same time. |
| 1399 | value is in seconds. |
| 1400 | Default: 600 |
Jesper Dangaard Brouer | e18f5fe | 2009-02-23 04:39:04 +0000 | [diff] [blame] | 1401 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1402 | regen_max_retry - INTEGER |
| 1403 | Number of attempts before give up attempting to generate |
| 1404 | valid temporary addresses. |
| 1405 | Default: 5 |
| 1406 | |
| 1407 | max_addresses - INTEGER |
Brian Haley | e79dc48 | 2010-02-22 12:27:21 +0000 | [diff] [blame] | 1408 | Maximum number of autoconfigured addresses per interface. Setting |
| 1409 | to zero disables the limitation. It is not recommended to set this |
| 1410 | value too large (or to zero) because it would be an easy way to |
| 1411 | crash the kernel by allowing too many addresses to be created. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1412 | Default: 16 |
| 1413 | |
YOSHIFUJI Hideaki | 778d80b | 2008-06-28 14:17:11 +0900 | [diff] [blame] | 1414 | disable_ipv6 - BOOLEAN |
Brian Haley | 9bdd8d4 | 2009-03-18 18:22:48 -0700 | [diff] [blame] | 1415 | Disable IPv6 operation. If accept_dad is set to 2, this value |
| 1416 | will be dynamically set to TRUE if DAD fails for the link-local |
| 1417 | address. |
YOSHIFUJI Hideaki | 778d80b | 2008-06-28 14:17:11 +0900 | [diff] [blame] | 1418 | Default: FALSE (enable IPv6 operation) |
| 1419 | |
Brian Haley | 56d417b | 2009-06-01 03:07:33 -0700 | [diff] [blame] | 1420 | When this value is changed from 1 to 0 (IPv6 is being enabled), |
| 1421 | it will dynamically create a link-local address on the given |
| 1422 | interface and start Duplicate Address Detection, if necessary. |
| 1423 | |
| 1424 | When this value is changed from 0 to 1 (IPv6 is being disabled), |
| 1425 | it will dynamically delete all address on the given interface. |
| 1426 | |
YOSHIFUJI Hideaki | 1b34be7 | 2008-06-28 14:18:38 +0900 | [diff] [blame] | 1427 | accept_dad - INTEGER |
| 1428 | Whether to accept DAD (Duplicate Address Detection). |
| 1429 | 0: Disable DAD |
| 1430 | 1: Enable DAD (default) |
| 1431 | 2: Enable DAD, and disable IPv6 operation if MAC-based duplicate |
| 1432 | link-local address has been found. |
| 1433 | |
Octavian Purdila | f7734fd | 2009-10-02 11:39:15 +0000 | [diff] [blame] | 1434 | force_tllao - BOOLEAN |
| 1435 | Enable sending the target link-layer address option even when |
| 1436 | responding to a unicast neighbor solicitation. |
| 1437 | Default: FALSE |
| 1438 | |
| 1439 | Quoting from RFC 2461, section 4.4, Target link-layer address: |
| 1440 | |
| 1441 | "The option MUST be included for multicast solicitations in order to |
| 1442 | avoid infinite Neighbor Solicitation "recursion" when the peer node |
| 1443 | does not have a cache entry to return a Neighbor Advertisements |
| 1444 | message. When responding to unicast solicitations, the option can be |
| 1445 | omitted since the sender of the solicitation has the correct link- |
| 1446 | layer address; otherwise it would not have be able to send the unicast |
| 1447 | solicitation in the first place. However, including the link-layer |
| 1448 | address in this case adds little overhead and eliminates a potential |
| 1449 | race condition where the sender deletes the cached link-layer address |
| 1450 | prior to receiving a response to a previous solicitation." |
| 1451 | |
Hannes Frederic Sowa | db2b620 | 2013-01-01 00:35:31 +0000 | [diff] [blame] | 1452 | ndisc_notify - BOOLEAN |
| 1453 | Define mode for notification of address and device changes. |
| 1454 | 0 - (default): do nothing |
| 1455 | 1 - Generate unsolicited neighbour advertisements when device is brought |
| 1456 | up or hardware address changes. |
| 1457 | |
Hannes Frederic Sowa | fc4eba5 | 2013-08-14 01:03:46 +0200 | [diff] [blame] | 1458 | mldv1_unsolicited_report_interval - INTEGER |
| 1459 | The interval in milliseconds in which the next unsolicited |
| 1460 | MLDv1 report retransmit will take place. |
| 1461 | Default: 10000 (10 seconds) |
| 1462 | |
| 1463 | mldv2_unsolicited_report_interval - INTEGER |
| 1464 | The interval in milliseconds in which the next unsolicited |
| 1465 | MLDv2 report retransmit will take place. |
| 1466 | Default: 1000 (1 second) |
| 1467 | |
Daniel Borkmann | f212781 | 2013-09-04 00:19:44 +0200 | [diff] [blame] | 1468 | force_mld_version - INTEGER |
| 1469 | 0 - (default) No enforcement of a MLD version, MLDv1 fallback allowed |
| 1470 | 1 - Enforce to use MLD version 1 |
| 1471 | 2 - Enforce to use MLD version 2 |
| 1472 | |
Hannes Frederic Sowa | b800c3b | 2013-08-27 01:36:51 +0200 | [diff] [blame] | 1473 | suppress_frag_ndisc - INTEGER |
| 1474 | Control RFC 6980 (Security Implications of IPv6 Fragmentation |
| 1475 | with IPv6 Neighbor Discovery) behavior: |
| 1476 | 1 - (default) discard fragmented neighbor discovery packets |
| 1477 | 0 - allow fragmented neighbor discovery packets |
| 1478 | |
Erik Kline | 7fd2561 | 2014-10-28 18:11:14 +0900 | [diff] [blame] | 1479 | optimistic_dad - BOOLEAN |
| 1480 | Whether to perform Optimistic Duplicate Address Detection (RFC 4429). |
| 1481 | 0: disabled (default) |
| 1482 | 1: enabled |
| 1483 | |
| 1484 | use_optimistic - BOOLEAN |
| 1485 | If enabled, do not classify optimistic addresses as deprecated during |
| 1486 | source address selection. Preferred addresses will still be chosen |
| 1487 | before optimistic addresses, subject to other ranking in the source |
| 1488 | address selection algorithm. |
| 1489 | 0: disabled (default) |
| 1490 | 1: enabled |
| 1491 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1492 | icmp/*: |
| 1493 | ratelimit - INTEGER |
| 1494 | Limit the maximal rates for sending ICMPv6 packets. |
Stephen Hemminger | 6dbf4bc | 2008-07-01 19:29:07 -0700 | [diff] [blame] | 1495 | 0 to disable any limiting, |
| 1496 | otherwise the minimal space between responses in milliseconds. |
| 1497 | Default: 1000 |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1498 | |
| 1499 | |
| 1500 | IPv6 Update by: |
| 1501 | Pekka Savola <pekkas@netcore.fi> |
| 1502 | YOSHIFUJI Hideaki / USAGI Project <yoshfuji@linux-ipv6.org> |
| 1503 | |
| 1504 | |
| 1505 | /proc/sys/net/bridge/* Variables: |
| 1506 | |
| 1507 | bridge-nf-call-arptables - BOOLEAN |
| 1508 | 1 : pass bridged ARP traffic to arptables' FORWARD chain. |
| 1509 | 0 : disable this. |
| 1510 | Default: 1 |
| 1511 | |
| 1512 | bridge-nf-call-iptables - BOOLEAN |
| 1513 | 1 : pass bridged IPv4 traffic to iptables' chains. |
| 1514 | 0 : disable this. |
| 1515 | Default: 1 |
| 1516 | |
| 1517 | bridge-nf-call-ip6tables - BOOLEAN |
| 1518 | 1 : pass bridged IPv6 traffic to ip6tables' chains. |
| 1519 | 0 : disable this. |
| 1520 | Default: 1 |
| 1521 | |
| 1522 | bridge-nf-filter-vlan-tagged - BOOLEAN |
Michael Milner | 516299d | 2007-04-12 22:14:23 -0700 | [diff] [blame] | 1523 | 1 : pass bridged vlan-tagged ARP/IP/IPv6 traffic to {arp,ip,ip6}tables. |
| 1524 | 0 : disable this. |
Pablo Neira Ayuso | 4981682 | 2012-05-08 19:36:44 +0200 | [diff] [blame] | 1525 | Default: 0 |
Michael Milner | 516299d | 2007-04-12 22:14:23 -0700 | [diff] [blame] | 1526 | |
| 1527 | bridge-nf-filter-pppoe-tagged - BOOLEAN |
| 1528 | 1 : pass bridged pppoe-tagged IP/IPv6 traffic to {ip,ip6}tables. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1529 | 0 : disable this. |
Pablo Neira Ayuso | 4981682 | 2012-05-08 19:36:44 +0200 | [diff] [blame] | 1530 | Default: 0 |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1531 | |
Pablo Neira Ayuso | 4981682 | 2012-05-08 19:36:44 +0200 | [diff] [blame] | 1532 | bridge-nf-pass-vlan-input-dev - BOOLEAN |
| 1533 | 1: if bridge-nf-filter-vlan-tagged is enabled, try to find a vlan |
| 1534 | interface on the bridge and set the netfilter input device to the vlan. |
| 1535 | This allows use of e.g. "iptables -i br0.1" and makes the REDIRECT |
| 1536 | target work with vlan-on-top-of-bridge interfaces. When no matching |
| 1537 | vlan interface is found, or this switch is off, the input device is |
| 1538 | set to the bridge interface. |
| 1539 | 0: disable bridge netfilter vlan interface lookup. |
| 1540 | Default: 0 |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1541 | |
Vlad Yasevich | 32e8d49 | 2008-07-08 16:43:29 -0700 | [diff] [blame] | 1542 | proc/sys/net/sctp/* Variables: |
| 1543 | |
| 1544 | addip_enable - BOOLEAN |
| 1545 | Enable or disable extension of Dynamic Address Reconfiguration |
| 1546 | (ADD-IP) functionality specified in RFC5061. This extension provides |
| 1547 | the ability to dynamically add and remove new addresses for the SCTP |
| 1548 | associations. |
| 1549 | |
| 1550 | 1: Enable extension. |
| 1551 | |
| 1552 | 0: Disable extension. |
| 1553 | |
| 1554 | Default: 0 |
| 1555 | |
| 1556 | addip_noauth_enable - BOOLEAN |
| 1557 | Dynamic Address Reconfiguration (ADD-IP) requires the use of |
| 1558 | authentication to protect the operations of adding or removing new |
| 1559 | addresses. This requirement is mandated so that unauthorized hosts |
| 1560 | would not be able to hijack associations. However, older |
| 1561 | implementations may not have implemented this requirement while |
| 1562 | allowing the ADD-IP extension. For reasons of interoperability, |
| 1563 | we provide this variable to control the enforcement of the |
| 1564 | authentication requirement. |
| 1565 | |
| 1566 | 1: Allow ADD-IP extension to be used without authentication. This |
| 1567 | should only be set in a closed environment for interoperability |
| 1568 | with older implementations. |
| 1569 | |
| 1570 | 0: Enforce the authentication requirement |
| 1571 | |
| 1572 | Default: 0 |
| 1573 | |
| 1574 | auth_enable - BOOLEAN |
| 1575 | Enable or disable Authenticated Chunks extension. This extension |
| 1576 | provides the ability to send and receive authenticated chunks and is |
| 1577 | required for secure operation of Dynamic Address Reconfiguration |
| 1578 | (ADD-IP) extension. |
| 1579 | |
| 1580 | 1: Enable this extension. |
| 1581 | 0: Disable this extension. |
| 1582 | |
| 1583 | Default: 0 |
| 1584 | |
| 1585 | prsctp_enable - BOOLEAN |
| 1586 | Enable or disable the Partial Reliability extension (RFC3758) which |
| 1587 | is used to notify peers that a given DATA should no longer be expected. |
| 1588 | |
| 1589 | 1: Enable extension |
| 1590 | 0: Disable |
| 1591 | |
| 1592 | Default: 1 |
| 1593 | |
| 1594 | max_burst - INTEGER |
| 1595 | The limit of the number of new packets that can be initially sent. It |
| 1596 | controls how bursty the generated traffic can be. |
| 1597 | |
| 1598 | Default: 4 |
| 1599 | |
| 1600 | association_max_retrans - INTEGER |
| 1601 | Set the maximum number for retransmissions that an association can |
| 1602 | attempt deciding that the remote end is unreachable. If this value |
| 1603 | is exceeded, the association is terminated. |
| 1604 | |
| 1605 | Default: 10 |
| 1606 | |
| 1607 | max_init_retransmits - INTEGER |
| 1608 | The maximum number of retransmissions of INIT and COOKIE-ECHO chunks |
| 1609 | that an association will attempt before declaring the destination |
| 1610 | unreachable and terminating. |
| 1611 | |
| 1612 | Default: 8 |
| 1613 | |
| 1614 | path_max_retrans - INTEGER |
| 1615 | The maximum number of retransmissions that will be attempted on a given |
| 1616 | path. Once this threshold is exceeded, the path is considered |
| 1617 | unreachable, and new traffic will use a different path when the |
| 1618 | association is multihomed. |
| 1619 | |
| 1620 | Default: 5 |
| 1621 | |
Neil Horman | 5aa93bc | 2012-07-21 07:56:07 +0000 | [diff] [blame] | 1622 | pf_retrans - INTEGER |
| 1623 | The number of retransmissions that will be attempted on a given path |
| 1624 | before traffic is redirected to an alternate transport (should one |
| 1625 | exist). Note this is distinct from path_max_retrans, as a path that |
| 1626 | passes the pf_retrans threshold can still be used. Its only |
| 1627 | deprioritized when a transmission path is selected by the stack. This |
| 1628 | setting is primarily used to enable fast failover mechanisms without |
| 1629 | having to reduce path_max_retrans to a very low value. See: |
| 1630 | http://www.ietf.org/id/draft-nishida-tsvwg-sctp-failover-05.txt |
| 1631 | for details. Note also that a value of pf_retrans > path_max_retrans |
| 1632 | disables this feature |
| 1633 | |
| 1634 | Default: 0 |
| 1635 | |
Vlad Yasevich | 32e8d49 | 2008-07-08 16:43:29 -0700 | [diff] [blame] | 1636 | rto_initial - INTEGER |
| 1637 | The initial round trip timeout value in milliseconds that will be used |
| 1638 | in calculating round trip times. This is the initial time interval |
| 1639 | for retransmissions. |
| 1640 | |
| 1641 | Default: 3000 |
| 1642 | |
| 1643 | rto_max - INTEGER |
| 1644 | The maximum value (in milliseconds) of the round trip timeout. This |
| 1645 | is the largest time interval that can elapse between retransmissions. |
| 1646 | |
| 1647 | Default: 60000 |
| 1648 | |
| 1649 | rto_min - INTEGER |
| 1650 | The minimum value (in milliseconds) of the round trip timeout. This |
| 1651 | is the smallest time interval the can elapse between retransmissions. |
| 1652 | |
| 1653 | Default: 1000 |
| 1654 | |
| 1655 | hb_interval - INTEGER |
| 1656 | The interval (in milliseconds) between HEARTBEAT chunks. These chunks |
| 1657 | are sent at the specified interval on idle paths to probe the state of |
| 1658 | a given path between 2 associations. |
| 1659 | |
| 1660 | Default: 30000 |
| 1661 | |
| 1662 | sack_timeout - INTEGER |
| 1663 | The amount of time (in milliseconds) that the implementation will wait |
| 1664 | to send a SACK. |
| 1665 | |
| 1666 | Default: 200 |
| 1667 | |
| 1668 | valid_cookie_life - INTEGER |
| 1669 | The default lifetime of the SCTP cookie (in milliseconds). The cookie |
| 1670 | is used during association establishment. |
| 1671 | |
| 1672 | Default: 60000 |
| 1673 | |
| 1674 | cookie_preserve_enable - BOOLEAN |
| 1675 | Enable or disable the ability to extend the lifetime of the SCTP cookie |
| 1676 | that is used during the establishment phase of SCTP association |
| 1677 | |
| 1678 | 1: Enable cookie lifetime extension. |
| 1679 | 0: Disable |
| 1680 | |
| 1681 | Default: 1 |
| 1682 | |
Neil Horman | 3c68198 | 2012-10-24 09:20:03 +0000 | [diff] [blame] | 1683 | cookie_hmac_alg - STRING |
| 1684 | Select the hmac algorithm used when generating the cookie value sent by |
| 1685 | a listening sctp socket to a connecting client in the INIT-ACK chunk. |
| 1686 | Valid values are: |
| 1687 | * md5 |
| 1688 | * sha1 |
| 1689 | * none |
| 1690 | Ability to assign md5 or sha1 as the selected alg is predicated on the |
stephen hemminger | 3b09adc | 2013-01-03 07:50:29 +0000 | [diff] [blame] | 1691 | configuration of those algorithms at build time (CONFIG_CRYPTO_MD5 and |
Neil Horman | 3c68198 | 2012-10-24 09:20:03 +0000 | [diff] [blame] | 1692 | CONFIG_CRYPTO_SHA1). |
| 1693 | |
| 1694 | Default: Dependent on configuration. MD5 if available, else SHA1 if |
| 1695 | available, else none. |
| 1696 | |
Vlad Yasevich | 32e8d49 | 2008-07-08 16:43:29 -0700 | [diff] [blame] | 1697 | rcvbuf_policy - INTEGER |
| 1698 | Determines if the receive buffer is attributed to the socket or to |
| 1699 | association. SCTP supports the capability to create multiple |
| 1700 | associations on a single socket. When using this capability, it is |
| 1701 | possible that a single stalled association that's buffering a lot |
| 1702 | of data may block other associations from delivering their data by |
| 1703 | consuming all of the receive buffer space. To work around this, |
| 1704 | the rcvbuf_policy could be set to attribute the receiver buffer space |
| 1705 | to each association instead of the socket. This prevents the described |
| 1706 | blocking. |
| 1707 | |
| 1708 | 1: rcvbuf space is per association |
stephen hemminger | 3b09adc | 2013-01-03 07:50:29 +0000 | [diff] [blame] | 1709 | 0: rcvbuf space is per socket |
Vlad Yasevich | 32e8d49 | 2008-07-08 16:43:29 -0700 | [diff] [blame] | 1710 | |
| 1711 | Default: 0 |
| 1712 | |
| 1713 | sndbuf_policy - INTEGER |
| 1714 | Similar to rcvbuf_policy above, this applies to send buffer space. |
| 1715 | |
| 1716 | 1: Send buffer is tracked per association |
| 1717 | 0: Send buffer is tracked per socket. |
| 1718 | |
| 1719 | Default: 0 |
| 1720 | |
| 1721 | sctp_mem - vector of 3 INTEGERs: min, pressure, max |
| 1722 | Number of pages allowed for queueing by all SCTP sockets. |
| 1723 | |
| 1724 | min: Below this number of pages SCTP is not bothered about its |
| 1725 | memory appetite. When amount of memory allocated by SCTP exceeds |
| 1726 | this number, SCTP starts to moderate memory usage. |
| 1727 | |
| 1728 | pressure: This value was introduced to follow format of tcp_mem. |
| 1729 | |
| 1730 | max: Number of pages allowed for queueing by all SCTP sockets. |
| 1731 | |
| 1732 | Default is calculated at boot time from amount of available memory. |
| 1733 | |
| 1734 | sctp_rmem - vector of 3 INTEGERs: min, default, max |
Max Matveev | a6e1204 | 2011-06-19 22:08:10 +0000 | [diff] [blame] | 1735 | Only the first value ("min") is used, "default" and "max" are |
| 1736 | ignored. |
| 1737 | |
| 1738 | min: Minimal size of receive buffer used by SCTP socket. |
| 1739 | It is guaranteed to each SCTP socket (but not association) even |
| 1740 | under moderate memory pressure. |
| 1741 | |
| 1742 | Default: 1 page |
Vlad Yasevich | 32e8d49 | 2008-07-08 16:43:29 -0700 | [diff] [blame] | 1743 | |
| 1744 | sctp_wmem - vector of 3 INTEGERs: min, default, max |
Max Matveev | a6e1204 | 2011-06-19 22:08:10 +0000 | [diff] [blame] | 1745 | Currently this tunable has no effect. |
Vlad Yasevich | 32e8d49 | 2008-07-08 16:43:29 -0700 | [diff] [blame] | 1746 | |
Bhaskar Dutta | 7238843 | 2009-09-03 17:25:47 +0530 | [diff] [blame] | 1747 | addr_scope_policy - INTEGER |
| 1748 | Control IPv4 address scoping - draft-stewart-tsvwg-sctp-ipv4-00 |
| 1749 | |
| 1750 | 0 - Disable IPv4 address scoping |
| 1751 | 1 - Enable IPv4 address scoping |
| 1752 | 2 - Follow draft but allow IPv4 private addresses |
| 1753 | 3 - Follow draft but allow IPv4 link local addresses |
| 1754 | |
| 1755 | Default: 1 |
| 1756 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1757 | |
Stephen Hemminger | 4edc2f3 | 2008-07-10 16:50:26 -0700 | [diff] [blame] | 1758 | /proc/sys/net/core/* |
Shan Wei | c60f6aa | 2012-04-26 16:52:52 +0000 | [diff] [blame] | 1759 | Please see: Documentation/sysctl/net.txt for descriptions of these entries. |
Wang Tinggong | 705efc3 | 2009-05-14 22:49:36 +0000 | [diff] [blame] | 1760 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1761 | |
Stephen Hemminger | 4edc2f3 | 2008-07-10 16:50:26 -0700 | [diff] [blame] | 1762 | /proc/sys/net/unix/* |
Wang Tinggong | 705efc3 | 2009-05-14 22:49:36 +0000 | [diff] [blame] | 1763 | max_dgram_qlen - INTEGER |
| 1764 | The maximum length of dgram socket receive queue |
| 1765 | |
| 1766 | Default: 10 |
| 1767 | |
| 1768 | |
| 1769 | UNDOCUMENTED: |
Stephen Hemminger | 4edc2f3 | 2008-07-10 16:50:26 -0700 | [diff] [blame] | 1770 | |
| 1771 | /proc/sys/net/irda/* |
| 1772 | fast_poll_increase FIXME |
| 1773 | warn_noreply_time FIXME |
| 1774 | discovery_slots FIXME |
| 1775 | slot_timeout FIXME |
| 1776 | max_baud_rate FIXME |
| 1777 | discovery_timeout FIXME |
| 1778 | lap_keepalive_time FIXME |
| 1779 | max_noreply_time FIXME |
| 1780 | max_tx_data_size FIXME |
| 1781 | max_tx_window FIXME |
| 1782 | min_tx_turn_time FIXME |