[squid-users] FW: Question about IPTABLES Configuration / Squid Proxy

From: Andrew Schmid <andrew.schmid_at_triplecanopy.com>
Date: Wed, 14 Oct 2009 17:19:27 -0400

Hi,

Here is quick info on my environment -
I have a CentOS 5.3 box server as firewall/gateway/router.
It has two interfaces
eth0 - public internetIP
eth1 - internal network IP (10.9.32.1)

The server hands out DHCP to all clients, and the server is the gateway.

I have installed squid proxy, and configured it to allow the local subnet,
and added transparent option.

I added this to my iptables
# http proxy redirect
-A PREROUTING -i eth1 -p tcp -m tcp --dport 80 -j DNAT --to-destination
10.9.32.1:3128
-A POSTROUTING -o eth0 -j MASQUERADE

The transparent caching now appears to work. However I came across this
article which says this: "WARNING: This method of interception is not
recommended. There are other methods such as Proxy.PAC and http_proxy
environment variable which are as effective and less intrusive when multiple
clients are involved."
http://wiki.squid-cache.org/ConfigExamples/Intercept/AtSource

So I am trying to find the better way to do this. This is what I have come
up with so far but does not seem to be working:
-A PREROUTING -i eth0 -p tcp --dport 80 -j ACCEPT
-A PREROUTING -p tcp --dport 80 -j REDIRECT --to-port 3128
-A POSTROUTING -o eth0 -j MASQUERADE

Is this correct? Does anyone have better suggestions on how to do this?

Thanks.

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Received on Wed Oct 14 2009 - 21:19:42 MDT

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