path: root/extensions/
diff options
author/C=DE/ST=Berlin/L=Berlin/O=Netfilter Project/OU=Development/CN=kaber/ </C=DE/ST=Berlin/L=Berlin/O=Netfilter Project/OU=Development/CN=kaber/>2007-02-24 15:11:33 +0000
committer/C=DE/ST=Berlin/L=Berlin/O=Netfilter Project/OU=Development/CN=kaber/ </C=DE/ST=Berlin/L=Berlin/O=Netfilter Project/OU=Development/CN=kaber/>2007-02-24 15:11:33 +0000
commit1905e3521e8401ad2ef912263265596d43e06a3c (patch)
tree206f258318c77aefd215255edfc680f39311dc6d /extensions/
parent6ef120e980e3e44bab704a01414a2ebec1c4c481 (diff)
iptables: add random option to SNAT (Eric Leblond)
Diffstat (limited to 'extensions/')
1 files changed, 5 insertions, 2 deletions
diff --git a/extensions/ b/extensions/
index 2d9427f..daef78f 100644
--- a/extensions/
+++ b/extensions/
@@ -7,7 +7,7 @@ modified (and all future packets in this connection will also be
mangled), and rules should cease being examined. It takes one type
of option:
-.BR "--to-source " "\fIipaddr\fP[-\fIipaddr\fP][:\fIport\fP-\fIport\fP]"
+.BR "--to-source " "\fIipaddr\fP[-\fIipaddr\fP][:\fIport\fP-\fIport\fP]" [ "--random" ]
which can specify a single new source IP address, an inclusive range
of IP addresses, and optionally, a port range (which is only valid if
the rule also specifies
@@ -17,7 +17,10 @@ or
If no port range is specified, then source ports below 512 will be
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.
+1024 or above. Where possible, no port alteration will If option
+.B "--random"
+is used then port mapping will be forcely randomized to avoid
+attacks based on port prediction (kernel >= 2.6.21).
In Kernels up to 2.6.10, you can add several --to-source options. For those