Re: [squid-users] Problem with squid / Plumtree Portal

From: Fred Clark <fredclrk_list@dont-contact.us>
Date: Wed, 23 Mar 2005 07:54:34 -0800 (PST)

Thanks so much for the explanation - perhaps we are
chasing the wrong windmill here...

We asssumed that the forwarding loops had a connection
to the dns failures, as they always showed up around
the same times as the loops and on the same node in
the cluster.

It alos seems odd that the only forarding loops we see
are from this particular environment and never appear
related to any other requests.

As the real prodduction impact issue is the dnsserver
failure, is there any way to keep this from happening,
short of going to internal dns? We would love to
impliment this, but unfortuanately we have too many
internal web sites that were written with short host
name sthat would fail if we didn't stay with
dnsserver...

Thanks again for the detailed response

Fred

--- Henrik Nordstrom <hno@squid-cache.org> wrote:
> On Tue, 22 Mar 2005, Fred Clark wrote:
>
> > A couple of months ago we started seeing
> forwarding
> > loop errors in the cache.log indicating issue with
> our
> > Plumtree Portal environment - extract as follows:
> >
> > 2005/03/04 16:23:03| WARNING: Forwarding loop
> detected
> > for:
> > GET /ptcs/gadgets/admin/gadget.jsp HTTP/1.0
> > Host: X.X.X.X:9080
> >
> > (Note that the true IP of the host has been
> changed to
> > X.X.X.X)
>
> A forwarding loop is when the same request is seen
> more than once by the
> same Squid, i.e. it forwarded (directly or
> indirectly) the request to
> itself.
>
> You should be able to determine why this happened by
> looking at the
> request headers reported together with this message,
> giving you the exact
> path how the request was forwarded among your
> Squids. This is the same
> method used by Squid to determines that there was a
> forwarding loop.
>
> Once you know the nature of the loop it is easier to
> try to picture how to
> avoid the loop. The reasons to forwarding loops can
> be many, but nearly
> always involves circular peering relationships.
>
> It may also be worth noticing that forwarding loops
> most often is not
> harmful as Squid when detecting a forwarding loop
> simply restricts it's
> forwarding methods to go direct, or if not allowed
> (never_direct) only use
> parents.
>
> Regards
> Henrik
>

                
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Received on Wed Mar 23 2005 - 08:54:39 MST

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