The "icmp" command only applies to ICMP traffic destined to the PIX, not to ICMP traffic through the PIX.
Also, you may want to change your deny statement to read:
icmp deny any echo outside
for traffic through the PIX, try turning on "debug icmp trace" and then ping from a host on the inside to something on the Internet. On the PIX you should see the echo-request go out and the echo-reply come back in.
Table of ContentsIntroductionVersion HistoryPossible Future
UpdatesDocuments PurposeNAT Operation in ASA 8.3+ SectionsRule Types
Network Object NATTwice NAT / Manual NATRule Types used per SectionNAT
Types used with Twice NAT / Manual NAT and Network Obje...
[toc:faq]Introduction:This document describes details on how NAT-T
works.Background:ESP encrypts all critical information, encapsulating
the entire inner TCP/UDP datagram within an ESP header. ESP is an IP
protocol in the same sense that TCP and UDP are I...