Various fixes (Herve Eychenne)
diff --git a/ip6tables.8 b/ip6tables.8
index afd2f9c..53a310c 100644
--- a/ip6tables.8
+++ b/ip6tables.8
@@ -27,7 +27,7 @@
.SH NAME
ip6tables \- IPv6 packet filter administration
.SH SYNOPSIS
-.BR "ip6tables [-t table] -[ADC] " "chain rule-specification [options]"
+.BR "ip6tables [-t table] -[AD] " "chain rule-specification [options]"
.br
.BR "ip6tables [-t table] -I " "chain [rulenum] rule-specification [options]"
.br
@@ -93,8 +93,9 @@
that table if it is not already there.
The tables are as follows:
-.TP
-.B "filter"
+.RS
+.TP .4i
+.BR "filter" :
This is the default table (if no -t option is passed). It contains
the built-in chains
.B INPUT
@@ -104,7 +105,7 @@
.B OUTPUT
(for locally-generated packets).
.TP
-.B "mangle"
+.BR "mangle" :
This table is used for specialized packet alteration. Until kernel
2.4.17 it had two built-in chains:
.B PREROUTING
@@ -118,6 +119,7 @@
(for altering packets being routed through the box), and
.B POSTROUTING
(for altering packets as they are about to go out).
+.RE
.SH OPTIONS
The options that are recognized by
.B ip6tables
@@ -157,10 +159,10 @@
.BR "-L, --list " "[\fIchain\fP]"
List all rules in the selected chain. If no chain is selected, all
chains are listed. As every other iptables command, it applies to the
-specified table (filter is the default), so NAT rules get listed by
-.br
- iptables -t nat -n -L
-.br
+specified table (filter is the default), so mangle rules get listed by
+.nf
+ ip6tables -t mangle -n -L
+.fi
Please note that it is often used with the
.B -n
option, in order to avoid long reverse DNS lookups.
@@ -169,9 +171,9 @@
(zero) option as well, in which case the chain(s) will be atomically
listed and zeroed. The exact output is affected by the other
arguments given. The exact rules are suppressed until you use
-.br
+.nf
ip6tables -L -v
-.br
+.fi
.TP
.BR "-F, --flush " "[\fIchain\fP]"
Flush the selected chain (all the chains in the table if none is given).
@@ -398,14 +400,14 @@
set. Flags are:
.BR "SYN ACK FIN RST URG PSH ALL NONE" .
Hence the command
-.br
+.nf
ip6tables -A FORWARD -p tcp --tcp-flags SYN,ACK,FIN,RST SYN
-.br
+.fi
will only match packets with the SYN flag set, and the ACK, FIN and
RST flags unset.
.TP
.B "[!] --syn"
-Only match TCP packets with the SYN bit set and the ACK and FIN bits
+Only match TCP packets with the SYN bit set and the ACK and RST bits
cleared. Such packets are used to request TCP connection initiation;
for example, blocking such packets coming in an interface will prevent
incoming TCP connections, but outgoing TCP connections will be
@@ -438,9 +440,9 @@
.BR "--icmpv6-type " "[!] \fItypename\fP"
This allows specification of the ICMP type, which can be a numeric
IPv6-ICMP type, or one of the IPv6-ICMP type names shown by the command
-.br
+.nf
ip6tables -p ipv6-icmp -h
-.br
+.fi
.SS mac
.TP
.BR "--mac-source " "[!] \fIaddress\fP"
@@ -607,15 +609,17 @@
returned:
.TP
.BI "--reject-with " "type"
-The type given can be
-.BR icmp6-no-route ,
-.BR no-route ,
-.BR icmp6-adm-prohibited ,
-.BR adm-prohibited ,
-.BR icmp6-addr-unreachable ,
-.BR addr-unreach ,
-.BR icmp6-port-unreachable ,
-.BR port-unreach ,
+The type given can be
+.nf
+.B " icmp6-no-route"
+.B " no-route"
+.B " icmp6-adm-prohibited"
+.B " adm-prohibited"
+.B " icmp6-addr-unreachable"
+.B " addr-unreach"
+.B " icmp6-port-unreachable"
+.B " port-unreach"
+.fi
which return the appropriate IPv6-ICMP error message (\fBport-unreach\fP is
the default). Finally, the option
.B tcp-reset
@@ -751,7 +755,8 @@
.B OUTPUT
are only traversed for packets coming into the local host and
originating from the local host respectively. Hence every packet only
-passes through one of the three chains; previously a forwarded packet
+passes through one of the three chains (except loopback traffic, which
+involves both INPUT and OUTPUT chains); previously a forwarded packet
would pass through all three.
.PP
The other main difference is that
@@ -805,12 +810,11 @@
.PP
Harald Welte wrote the ULOG target, TTL match+target and libipulog.
.PP
-The Netfilter Core Team is: Marc Boucher, Jozsef Kadlecsik, James Morris,
-Harald Welte and Rusty Russell.
+The Netfilter Core Team is: Marc Boucher, Martin Josefsson, Jozsef Kadlecsik,
+James Morris, Harald Welte and Rusty Russell.
.PP
ip6tables man page created by Andras Kis-Szabo, based on
iptables man page written by Herve Eychenne <rv@wallfire.org>.
-
.\" .. and did I mention that we are incredibly cool people?
.\" .. sexy, too ..
.\" .. witty, charming, powerful ..
diff --git a/iptables.8 b/iptables.8
index a166a8b..b79f1ec 100644
--- a/iptables.8
+++ b/iptables.8
@@ -25,7 +25,7 @@
.SH NAME
iptables \- administration tool for IPv4 packet filtering and NAT
.SH SYNOPSIS
-.BR "iptables [-t table] -[ADC] " "chain rule-specification [options]"
+.BR "iptables [-t table] -[AD] " "chain rule-specification [options]"
.br
.BR "iptables [-t table] -I " "chain [rulenum] rule-specification [options]"
.br
@@ -91,8 +91,9 @@
that table if it is not already there.
The tables are as follows:
-.TP
-.B "filter"
+.RS
+.TP .4i
+.BR "filter" :
This is the default table (if no -t option is passed). It contains
the built-in chains
.B INPUT
@@ -102,7 +103,7 @@
.B OUTPUT
(for locally-generated packets).
.TP
-.B "nat"
+.BR "nat" :
This table is consulted when a packet that creates a new
connection is encountered. It consists of three built-ins:
.B PREROUTING
@@ -112,7 +113,7 @@
.B POSTROUTING
(for altering packets as they are about to go out).
.TP
-.B "mangle"
+.BR "mangle" :
This table is used for specialized packet alteration. Until kernel
2.4.17 it had two built-in chains:
.B PREROUTING
@@ -126,6 +127,7 @@
(for altering packets being routed through the box), and
.B POSTROUTING
(for altering packets as they are about to go out).
+.RE
.SH OPTIONS
The options that are recognized by
.B iptables
@@ -166,9 +168,9 @@
List all rules in the selected chain. If no chain is selected, all
chains are listed. As every other iptables command, it applies to the
specified table (filter is the default), so NAT rules get listed by
-.br
+.nf
iptables -t nat -n -L
-.br
+.fi
Please note that it is often used with the
.B -n
option, in order to avoid long reverse DNS lookups.
@@ -177,9 +179,9 @@
(zero) option as well, in which case the chain(s) will be atomically
listed and zeroed. The exact output is affected by the other
arguments given. The exact rules are suppressed until you use
-.br
+.nf
iptables -L -v
-.br
+.fi
.TP
.BR "-F, --flush " "[\fIchain\fP]"
Flush the selected chain (all the chains in the table if none is given).
@@ -450,12 +452,13 @@
.TP
.BI "--helper " "string"
Matches packets related to the specified conntrack-helper.
-.TP
+.RS
+.PP
string can be "ftp" for packets related to a ftp-session on default port.
For other ports append -portnr to the value, ie. "ftp-2121".
-.br
+.PP
Same rules apply for other conntrack-helpers.
-.br
+.RE
.SS icmp
This extension is loaded if `--protocol icmp' is specified. It
provides the following option:
@@ -463,9 +466,9 @@
.BR "--icmp-type " "[!] \fItypename\fP"
This allows specification of the ICMP type, which can be a numeric
ICMP type, or one of the ICMP type names shown by the command
-.br
+.nf
iptables -p icmp -h
-.br
+.fi
.SS length
This module matches the length of a packet against a specific value
or range of values.
@@ -652,9 +655,9 @@
set. Flags are:
.BR "SYN ACK FIN RST URG PSH ALL NONE" .
Hence the command
-.br
+.nf
iptables -A FORWARD -p tcp --tcp-flags SYN,ACK,FIN,RST SYN
-.br
+.fi
will only match packets with the SYN flag set, and the ACK, FIN and
RST flags unset.
.TP
@@ -732,7 +735,8 @@
.BR "-p udp" ).
If no port range is specified, then the destination port will never be
modified.
-.TP
+.RS
+.PP
You can add several --to-destination options. If you specify more
than one destination address, either via an address range or multiple
--to-destination options, a simple round-robin (one after another in
@@ -862,13 +866,15 @@
.TP
.BI "--reject-with " "type"
The type given can be
-.BR icmp-net-unreachable ,
-.BR icmp-host-unreachable ,
-.BR icmp-port-unreachable ,
-.BR icmp-proto-unreachable ,
-.BR icmp-net-prohibited ,
-.BR "icmp-host-prohibited or"
-.BR "icmp-admin-prohibited (*)"
+.nf
+.B " icmp-net-unreachable"
+.B " icmp-host-unreachable"
+.B " icmp-port-unreachable"
+.B " icmp-proto-unreachable"
+.B " icmp-net-prohibited"
+.B " icmp-host-prohibited or"
+.B " icmp-admin-prohibited (*)"
+.fi
which return the appropriate ICMP error message (\fBport-unreachable\fP is
the default). The option
.B tcp-reset
@@ -900,7 +906,8 @@
mapped to other ports below 512: those between 512 and 1023 inclusive
will be mapped to ports below 1024, and other ports will be mapped to
1024 or above. Where possible, no port alteration will occur.
-.TP
+.RS
+.PP
You can add several --to-source options. If you specify more
than one source address, either via an address range or multiple
--to-source options, a simple round-robin (one after another in
@@ -917,19 +924,25 @@
problem are that everything works fine from your Linux
firewall/router, but machines behind it can never exchange large
packets:
-.br
- 1) Web browsers connect, then hang with no data received.
-.br
- 2) Small mail works fine, but large emails hang.
-.br
- 3) ssh works fine, but scp hangs after initial handshaking.
-.br
+.PD 0
+.RS 0.1i
+.TP 0.3i
+1)
+Web browsers connect, then hang with no data received.
+.TP
+2)
+Small mail works fine, but large emails hang.
+.TP
+3)
+ssh works fine, but scp hangs after initial handshaking.
+.RE
+.PD
Workaround: activate this option and add a rule to your firewall
configuration like:
-.br
+.nf
iptables -A FORWARD -p tcp --tcp-flags SYN,RST SYN \\
-.br
-j TCPMSS --clamp-mss-to-pmtu
+.fi
.TP
.BI "--set-mss " "value"
Explicitly set MSS option to specified value.
@@ -946,9 +959,9 @@
.TP
.BI "--set-tos " "tos"
You can use a numeric TOS values, or use
-.br
+.nf
iptables -j TOS -h
-.br
+.fi
to see the list of valid TOS names.
.SS ULOG
This target provides userspace logging of matching packets. When this
@@ -996,7 +1009,8 @@
.B OUTPUT
are only traversed for packets coming into the local host and
originating from the local host respectively. Hence every packet only
-passes through one of the three chains; previously a forwarded packet
+passes through one of the three chains (except loopback traffic, which
+involves both INPUT and OUTPUT chains); previously a forwarded packet
would pass through all three.
.PP
The other main difference is that
@@ -1013,13 +1027,11 @@
optional extension modules. This should simplify much of the previous
confusion over the combination of IP masquerading and packet filtering
seen previously. So the following options are handled differently:
-.br
+.nf
-j MASQ
-.br
-M -S
-.br
-M -L
-.br
+.fi
There are several other changes in iptables.
.SH SEE ALSO
.BR iptables-save (8),
@@ -1054,7 +1066,6 @@
James Morris, Harald Welte and Rusty Russell.
.PP
Man page written by Herve Eychenne <rv@wallfire.org>.
-
.\" .. and did I mention that we are incredibly cool people?
.\" .. sexy, too ..
.\" .. witty, charming, powerful ..