The PIX will pass traffic and support you testing purposes as long as the failover cable is within spec (I've seen a number of copper failover and state cables that are about 10 inches in length..i.e. out of spec physically).
The problem with a cross over cable for the failover link and the reason an intermediate switch is recommended is, "What happens when one of the failover interfaces on the Primary or Standby fails?
The standby will miss hellos from the primary, and begin testing, but which interface is down? The first test the firewalls will perform is a Link UP/Down test....once again, who has failed? Because the firewalls will be able to communicate on other interfaces there will be no failover. So what happens? To quote the manual, "If the firewall does not receive a response on the failover link only, then the unit does not failover. The failover link is marked as failed. You should restore the failover link as soon as possible because the unit cannot fail over to the standby while the failover link is down."
Will it pass traffic? Yes. Do you derive all the HA benifits of failover? No.
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...
Table of Contents 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 an...