We have a VPN IPSec tunnel established between two Cisco Routers. Every night (around 01:00am), we receive a snmp trap indicating that the IPSec Phase-1 tunnel becomes inactive. It last about 01 hour and then, we receive another snmp trap indicating that the IPSec Phase-1 tunnel becomes active again. Very strange beacuse, when we consult the show log of these two routers, there are no messages related to this IPSec Phase-1 tunnel (for the determined date and hour). Very strange also because, the SNMP traffic is not interrupted between the two cisco routers (we dont't receive SNMP timeout from SNMP manager when it tries to reach the SNMP agent behind these two routers). Normally when the IPSec Phase-1 tunnel becomes inactive, the tunnel is no more established and available and the SNMP traffic must be interrupted between these two routers ==> SNMP Timeout between SNMP manager and SNMP agents.
What is the just explanation for continuation of traffic between these two routers (with Phase-1 tunnel inactive) ?
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...