Varnish, between Zeus and Apache

Michael Alger varnish at
Wed Mar 2 09:32:42 CET 2011

On Tue, Mar 01, 2011 at 11:54:32AM -0500, Dan Gherman wrote:
> I am confronting with this situation: I manage a Zeus load-balancer
> cluster who has Apache as a webserver on the nodes in the backend.
> When Zeus load-balances a connection to an Apache server or
> Apache-based application, the connection appears to originate from the
> Zeus machine.Zeus provide an Apache module to work around this. Zeus
> automatically inserts a special 'X-Cluster-Client-Ip' header into each
> request, which identifies the true source address of the request.
> [...]
> Is there a way to have a workaround, like that Apache module, so I can
> then send to Apache the true source address of the request? My
> error.log is flooded with the usual messages " Ignoring
> X-Cluster-Client-Ip 'client_ip' from non-Load Balancer machine
> 'node_ip'

It sounds like Varnish is sending the headers it receives, but the
Apache module only respects the X-Cluser-Client-IP header when it's
received from a particular IP address(es). See if there's a way to
configure the module to accept it from Varnish, i.e. as if Varnish is
the load-balancer. There's probably some existing configuration which
has the IP address of the Zeus load-balancer.

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