WARNING: (B) ‘::/0’ is a subnetwork of (A) ‘::/0’
I had this warning when restarting squid 3. I had a line left over from squid 2:
acl all src 0.0.0.0/0.0.0.0
which I had subsequently changed to
acl all src all
as I received a CIDR warning. So to get rid of the subnetwork warning I removed the line altogether, as Squid 3 has this ‘all’ rule built in anyway.