Configure Forefront TMG to allow pings from internal hosts
Creating a firewall access rule in Forefront Threat Management Gateway to Allow ICMP echo and ICMP echo replies. This is called the "Ping" protocol :-( in Forefront TMG
I'm still trying to figure out why an explicit ICMP echo request and ICMP echo reply rule does NOT work on Forefront (There must be some MS Magic behind the Ping "protocol")