Re: [PLUG] iptables question

[Stephen Gran <steve@lobefin.net>]

On Mon, Dec 01, 2003 at 01:44:05PM -0500, Ian Reinhart Geiser said:
> Hi,
> Im not even sure how to google for this question so if anyone could
> even give me a hint on what to google for that would be awesome.
> 
> Basicly I have an iptables based firewall running on debian stable.  I
> am already forwarding ports with success but now I would like to do
> port redirection based on the hostname requested.  IE, ssh to
> cvs.kdedevelopers.org currently gives me the firewall... but I would
> like to have it forward to the system that hosts cvs.kdedevelopers.org
> that lies on a private IP.  Can I do this without changing the port
> SSH is on the firewall?
> 
> 	Any hints would be great.
> 
> Cheers
> 	-ian reinhart geiser

I take it you have an arrangement like this:

Internet
   |
   |
Firewall
|  | | |
LAN boxes

Correct?

And you want the firewall to redirect incoming ssh requests to one of
the LAN boxes.

I don't think trying to redirect by fqdn is a good idea (think DNS
timeouts and such), but doing it by IP is straightforward.

iptables -t nat -A PREROUTING -i eth0 -p tcp --dport 22 -d $IP_OF_CVS \
    -j DNAT --to-destination $INTERNAL_IP

HTH,
-- 
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|  Stephen Gran                  | "And I don't like doing silly things    |
|  steve@lobefin.net             | (except on purpose)."              --   |
|  http://www.lobefin.net/~steve | Larry Wall in                           |
|  			         | <1992Jul3.191825.14435@netlabs.com>     |
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