For a customer I am providing a Ipsec VPN client connection with a Cisco 851 router. The Wan side of the router is connected through a wireless network to the LAN side of a SnapGear router from another vendor. There is two more SnapGear routers connected over the same wireless network to the first SnapGear router as well. MTU is set to 1380 on the LAN interface of the first router, and also to 1380 on the WAN side of the other two routers. VPN sessions through theese routers works fine. I have tried to set "ip mtu 1380" on the WAN interface of the Cisco router. I am then able to connect, and receive a ip-address on the LAN. As soon as I generate trafic (icmp, http or else) the session is disconnected.
Everything works fine if I connect through the Cisco router only. The problem occurs when establishing a sesion through two routers. I have attached a network diagram.
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...