How to pass certain URL to parent proxy in squid?

Question

I would like to retrieve certain sites or domains via uplink proxy in squid. I would like to have a list of such sites. How to do that?

I see directive always_direct, but I need opposite: pass all requests directly, but only some of them -- to peer.

Is this possible?

Answer 1

You use the cache_peer config option to define a peer or parent, and you use cache_peer_access to force all requests matching a particular squid acl to use that peer.

For example:

cache_peer squid2.example.com sibling 3128 3130
acl alwayspeer dstdomain foo.example.com bar.example.com
cache_peer_access squid2.example.com allow alwayspeer

That will force all requests for those two domains (foo.example.com and bar.example.com) to go via the peer (squid2.example.com).

NOTE: alwayspeer is just an arbitrary name I chose for this acl.

If you also want to restrict usage of that peer to ONLY the domains listed in the alwayspeer acl, add the following line:

cache_peer_access squid2.example.com deny !alwayspeer

Any squid acl type can be used, not just dstdomain. e.g. url_regex or urlpath_regex (or dstdom_regex) if you want the acl to regex match part or all of a URL (or domain).

Finally, multiple acls can be allowed or denied with cache_peer_access rules. Note that the order of rules is significant (first matching rule wins).