Hi,
squid 3.5 seems to have some trouble starting the ICMP Pinger, from /var/squid/logs/cache.log:
2015/11/02 00:02:06 kid1| Pinger socket opened on FD 16
015/11/02 00:02:06| pinger: Initialising ICMP pinger ...
2015/11/02 00:02:06| icmp_sock: (13) Permission denied
2015/11/02 00:02:06| pinger: Unable to start ICMP pinger.
2015/11/02 00:02:06| icmp_sock: (13) Permission denied
2015/11/02 00:02:06| pinger: Unable to start ICMPv6 pinger.
2015/11/02 00:02:06| FATAL: pinger: Unable to open any ICMP sockets.
2015/11/02 00:02:34 kid1| recv: (146) Connection refused
2015/11/02 00:02:34 kid1| Closing Pinger socket on FD 16
2015/11/02 00:02:34 kid1| netdbExchangeHandleReply: corrupt data, aborting