| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | |
| 2 | There are a few network parameters that can be tuned to better match |
| 3 | the kernel to your system hardware and intended usage. The defaults |
| 4 | are usually a good choice for 99% of the people 99% of the time, but |
| 5 | you should be aware they do exist and can be changed. |
| 6 | |
| 7 | The current list of parameters can be found in the files: |
| 8 | |
| 9 | linux/net/TUNABLE |
| 10 | Documentation/networking/ip-sysctl.txt |
| 11 | |
| 12 | Some of these are accessible via the sysctl interface, and many more are |
| 13 | scheduled to be added in this way. For example, some parameters related |
| 14 | to Address Resolution Protocol (ARP) are very easily viewed and altered. |
| 15 | |
| 16 | # cat /proc/sys/net/ipv4/arp_timeout |
| 17 | 6000 |
| 18 | # echo 7000 > /proc/sys/net/ipv4/arp_timeout |
| 19 | # cat /proc/sys/net/ipv4/arp_timeout |
| 20 | 7000 |
| 21 | |
| 22 | Others are already accessible via the related user space programs. |
| 23 | For example, MAX_WINDOW has a default of 32 k which is a good choice for |
| 24 | modern hardware, but if you have a slow (8 bit) Ethernet card and/or a slow |
| 25 | machine, then this will be far too big for the card to keep up with fast |
| 26 | machines transmitting on the same net, resulting in overruns and receive errors. |
| 27 | A value of about 4 k would be more appropriate, which can be set via: |
| 28 | |
| 29 | # route add -net 192.168.3.0 window 4096 |
| 30 | |
| 31 | The remainder of these can only be presently changed by altering a #define |
| 32 | in the related header file. This means an edit and recompile cycle. |
| 33 | |
| 34 | Paul Gortmaker 06/96 |