Hi Len,
SOL7366 (
Click here) details the steps required to allow ICMP through a SNAT:
A SNAT passes ICMP traffic when SNAT Packet Forwarding is set to All Traffic. The All Traffic setting specifies that the BIG-IP system forwards any IP packets originating from a SNAT member for all traffic types.
To configure a SNAT to forward all traffic, perform the following procedure:
1. Log in to the Configuration utility.
2. Click System, then click General Properties.
3. From the Local Traffic menu, select General.
4. Change the SNAT Packet Forwarding setting to All Traffic.
5. Click Update.
What type of SNAT(s) have you defined?
Aaron