Problems with sibling caches + multicast

We are running Squid 2.1PATCH1 on 3 FreeBSD 3.0 machines trying to run a
cluster of caches in a siblings peering arrangement using multicast for ICP
queries. The caches seem to be talking to each other fine.

When the client sends a HTTP requested that isn't cached on the configured
cache, the cache sends out an ICP multicast query, all other caches recieve
this fine and respond. Either with UDP_MISS or UDP_HIT.

The problem is, if the other caches respond with a UDP_HIT the orginal cache
still fetches the object directly, rather than fetching the object from the
sibling. Why?

Here is our config for all three caches:

Cache 1
------------

mcast_groups 224.9.9.9
cache_peer 224.9.9.9 multicast 3128 3130 ttl=10
cache_peer cache2 sibling 3128 3130 multicast-responder proxy-only
cache_peer cache3 sibling 3128 3130 multicast-responder proxy-only
icp_hit_stale on

Cache 2
------------

mcast_groups 224.9.9.9
cache_peer 224.9.9.9 multicast 3128 3130 ttl=10
cache_peer cache1 sibling 3128 3130 multicast-responder proxy-only
cache_peer cache3 sibling 3128 3130 multicast-responder proxy-only
icp_hit_stale on

Cache 3
------------

mcast_groups 224.9.9.9
cache_peer 224.9.9.9 multicast 3128 3130 ttl=10
cache_peer cache1 sibling 3128 3130 multicast-responder proxy-only
cache_peer cache2 sibling 3128 3130 multicast-responder proxy-only
icp_hit_stale on
Received on Wed Nov 25 1998 - 14:29:29 MST