RE: Quick Question

["Aldo S. Lagana" <alagana@discmail.com>]

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It is fairly easy - 
 
The redirect to squid is done in the PREROUTING chain and
SNAT is done in POSTROUTING...
 
so if it is port 80 it will get picked up first, otherwise it will be
SNAT'ted in the POSTROUTING chain:
 
iptables -t nat -A PREROUTING -i $INTERNAL_INTERFACE -p tcp --dport 80
-j REDIRECT --to-port 3128
 
iptables -t nat -A POSTROUTING -o $INTERNET_INTERFACE -j SNAT
--to-source $INTERNET_IP


-----Original Message-----
From: netfilter-admin@lists.samba.org
[mailto:netfilter-admin@lists.samba.org] On Behalf Of Mike Atlas
Sent: Thursday, May 30, 2002 4:10 PM
To: netfilter@lists.samba.org
Subject: Quick Question


Hello Everyone. I hope you all can help me, I'm sure you can (it seems
like a pretty simple problem).
 
I am setting up a Squid proxy server to run in transparent mode. To do
this, I need to forward all port 80 and 443 traffic to squids' port,
3128. Additionally, I would like all other traffic on all other ports to
forward on to the router. 
 
I have found a script to forward port 80 to squid (note: eth1 is my
internal interface, eth0 is external):
 
iptables -t nat -A PREROUTING -i eth1 -p tcp --dport 80 -j REDIRECT
--to-port 3128
 
I assume I can run the same line for 443:
 
iptables -t nat -A PREROUTING -i eth1 -p tcp --dport 443 -j REDIRECT
--to-port 3128
 
 
However, what can I use to forward EVERYTHING that is not port 80 out of
the eth0 interface, to our router (192.168.0.2)?
I know it has something to do with --dport ! 80, but I can't figure it
out.
 
Thanks for your help.
BTW, this is RedHat 72. if that makes any difference. Linux kernel
2.4.9-31.
 
-mike

______________________________________________
Mike Atlas                          703.385.8362(v)
Senior System Engineer    703.385.3674(f)
Vista Innovation                www.vistainnovation.com 

 


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