Core issue
The client is not configured to use PIX as default gateway.
Resolution
- Verify that the client's default gateway is set to the inside interface of the PIX.
- Verify that the PIX configuration has a translation (either a nat and corresponding global statement or a static statement) for the inside host. To check the translation, issue the show xlate command.
- Verify that there is an access-list statement applied to the outside interface permitting Internet Control Message Protocol (ICMP) echo-replies back in through the PIX. (Conduits can also be used.)
For more information about these PIX commands, check the Cisco Secure PIX Firewall Command References for your software version.