Hi there I have been playing with my PING packet filters trying to get my ISA Server to respond to external PING requests. The thing is I now have got it working, but I want to cleanup the mess I made and cannot for the life of me figure out which packet filters need to remain and which can be removed. Here are my PING packet filters: ICMP All Outbound ICMP Unreachable ICMP Ping Response ICMP Ping Query (This is the one that appears to solve my original problem) ICMP Source Quench ICMP Timeout ICMP Unreachable Could someone please let me know which of the above packet filter types can in fact be removed? Cheers William R.