Synopsis
As discussed in Section
10.6.3, Squid supports receiving ICP queries via multicast. This
option specifies a list of multicast addresses Squid should join to
receive these ICP queries.
Tip
IP multicast is a very tricky and often fragile feature of the
Internet. I strongly recommend you avoid using multicast for ICP
unless you are already familiar with it. Don’t try to guess
appropriate values for these directives, and don’t expect it to work
the first time.