Question : Cannot ping outside IP of Firebox

I cannot ping the outside interface of the Watchguard x550e that I'm trying to setup up. The network layout is as follows,

Internal IP - 192.168.10.x
Outside IP - 65.220.x.x

I can ping all inside hosts and I can ping external IPs if plugged in directly in into the firebox with a laptop that is not part of the domain. Its only when I try to use a computer within the Win2008 domain that I fail. Any pointers are appreciated.

Answer : Cannot ping outside IP of Firebox

How have you configured the ICMP service; is it like this:
Enabled and allowed; from any; to any

If yes, you would not get any response.

Depending on which machine you wish to respond to ICMP echo packets you should configure the service as:
Enabled and allowed; from any OR Specific-ip-subnet-or-ip; to external-ip->internal-ip-of-machine

See article below on adding static NAT:
http://watchguard.custhelp.com/app/answers/detail/a_id/1295/kw/adding%20static%20NAT/session/L3NpZC9MVUVNX2k4aw%3D%3D

Thank you.