diff options
author | Florian Westphal <fw@strlen.de> | 2013-07-12 23:29:28 +0200 |
---|---|---|
committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2013-08-06 18:44:03 +0200 |
commit | f0d75111d788b2424f543ff2246caa2dc980aa93 (patch) | |
tree | 78a95b273af4c280f85e85014182857ccf9777e2 /extensions/libxt_socket.man | |
parent | 64d45792fe8f50294034bb699ff74ecae178e975 (diff) |
extensions: libxt_socket: update man page
Document --nowildcard option and its implications when using -m socket
to intercept packets.
While at it, update man page with Balazs Scheidlers comments from
nf_tproxy_core.h in kernel tree to better explain how lookup is performed.
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Diffstat (limited to 'extensions/libxt_socket.man')
-rw-r--r-- | extensions/libxt_socket.man | 21 |
1 files changed, 19 insertions, 2 deletions
diff --git a/extensions/libxt_socket.man b/extensions/libxt_socket.man index 41e8d674..2ef32cec 100644 --- a/extensions/libxt_socket.man +++ b/extensions/libxt_socket.man @@ -1,5 +1,22 @@ -This matches if an open socket can be found by doing a socket lookup on the -packet. +This matches if an open TCP/UDP socket can be found by doing a socket lookup on the +packet. It matches if there is an established or non\-zero bound listening +socket (possibly with a non\-local address). The lookup is performed using +the \fBpacket\fP tuple of TCP/UDP packets, or the original TCP/UDP header +\fBembedded\fP in an ICMP/ICPMv6 error packet. .TP \fB\-\-transparent\fP Ignore non-transparent sockets. +.TP +\fB\-\-nowildcard\fP +Do not ignore sockets bound to 'any' address. +The socket match won't accept zero\-bound listeners by default, since +then local services could intercept traffic that would otherwise be forwarded. +This option therefore has security implications when used to match traffic being +forwarded to redirect such packets to local machine with policy routing. +When using the socket match to implement fully transparent +proxies bound to non\-local addresses it is recommended to use the \-\-transparent +option instead. +.PP +Example (assuming packets with mark 1 are delivered locally): +.IP +\-t mangle \-A PREROUTING \-m socket \-\-transparent \-j MARK \-\-set\-mark 1 |