[squid-users] (squid 3) Reverse proxy - acceleration for multiple webservers with multiple virtual hosts

Excuse me if this topic was already discussed - I may be blind or just
not enough smart to find it either in archives or websites.

First: reality check - is it possible to use single (for start) Squid as
acceleration cache for multiple webservers, each one having multiple
virtual hosts in an architecture like that:

inet <-> gateway with proxying apache <-> squid <-> webservers farm

Each of webservers has some number of apaches with virtual hosts or
java-based web applications operating on HTTP.

If it's possible, could someone share a simple example config file (for
squid 3) for such setup because my attempts are failing. What I'm
trying to use looks like that (insignificant options left out):

http_port 80 vport
redirect_rewrites_host_header off
http_access allow all
http_reply_access allow all
cache_peer webserver1.internal parent 80 0
no-query originserver name=webserver1
cache_peer_access webserver1 allow all
cache_peer_domain webserver1 webserver1.external.com

Now, when I try to browse http://webserver1.external.com (which is of
course fake for example's sake) I get:

<cite>
While trying to retrieve the URL: http://<private_ip_of_squid>/

The following error was encountered:

* Unable to forward this request at this time.

This request could not be forwarded to the origin server or to any
parent caches. The most likely cause for this error is that:

* The cache administrator does not allow this cache to make direct
connections to origin servers, and
* All configured parent caches are currently unreachable.
</cite>

The squid machine reaches the webserver1 with no problems using ping,
telnet, links etc, so I guess it's not a connectivity problem (tcpdump
shows no traffic leaving squid like it doesn't even try). If this is
ACL problem, I can't see where and what rule should I put.

Thanks in advance for any enlightenments.

-- 
Tomasz Marciniak