We have built an IPSEC tunnel between a CheckPoint firewall and a Cisco 3725 router. Every 5 minutes a server inside the firewall sends a "keepalive" packet to a server inside the router. The server logs a socket error indicating that the IPSEC socket has gone down. The server then goes through the effort to tear down his end of the tunnel,
Just to be clear; where does the IPsec tunnel terminate? Is the IPsec tunnel between the router and firewall or is it between the two servers?
From what you are saying (server IPsec sockets, and server exchanging keys) it sounds like the tunnel endpoints are the servers? In this case the firewall and router just need to pass the traffic and not actively participate in IPsec i.e. the "show crypto ..." commands won't show anything meaningful.
If on the other hand the tunnel is between the router and firewall the servers would effectively have no knowledge of the IPsec tunnel. The tunnel is just another layer3 IP hop in the cloud between the servers.
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...