Re: [squid-users] forwarding loop in interception caching

Please keep replies on the list.

lör 2006-11-04 klockan 10:22 +0200 skrev genco yilmaz:

> Actually I was aware of it:) but It didn't come into my mind that it
> can cause such a thing. (a bit lack of experience)

Redirectors does not cause loops if used correctly, but not being aware
of them makes it easy to misunderstand the loop.

> I know that visible_hostname is unique in all of the proxy servers
> and we dont have any cache_peer lines.

Ok.

> For interception in iptables we have;
>
> iptables -t nat -A PREROUTING -i eth0 -p tcp --dport 80 -j REDIRECT
> --to-port 8080

Ok.

> I am not sure but it seems that loop is due to the messages sending
> back and forth between redirector and squid but I cannot find how it
> is happening.

Requests is not sent between the redirector and Squid. Squid only asks
the redirector about the URL and the redirector returns a new URL that
Squid should use instead.

A loop occurs if the URL after redirection points back to Squid.

A loop also occurs in interception mode if the request initiated by
Squid is intercepted again.

So far nothing obvious why you are seeing loops, but what does
access.log say?

Also which Squid version are you using? Interception mode is somewhat
broken in 2.6.STABLE1 causing "failed to select source" errors.

Regards
Henrik