Re: Altering a packet's port

["Nicolas Ross" <rossnick-lists@cybercat.ca>]

I saw that in the man page, but I need to do this for ALL hosts to specific 
subnets, and many hosts. So I'll have to define one rule for EACH host I 
need a redirect (something like 50 to 75) ?

Nicolas

----- Original Message ----- 
From: "Sertys" <sertys@supportivo.org>
To: "Netfilter list" <netfilter@lists.netfilter.org>
Sent: Monday, March 21, 2005 5:00 PM
Subject: Re: Altering a packet's port


On Mon, 21 Mar 2005 15:43:44 -0500, Nicolas Ross
<rossnick-lists@cybercat.ca> wrote:

> What I want to do, is that if a packet originites from the local net 
> (192.168.7.x) on tcp port 22, that the final destination of the packet 
> would wtill be the same host, but on port 8022...
> (...)

Redirect works on local hooks. Just DNAT it, dude.
iptables -t nat -A PREROUTING -p tcp -s 192.168.x.x --dport 22 -j DNAT
--to-destination f.g.h.i:8022

It's crucial to define dport, not sport, cause your sport is not 22, it's
a client port > 1024 and random.