I have a situation in which I require to set-up IPSec tunnel in between two 1841 routers. This is normally two minutes job, in this case however one of the routers sits on a private LAN behind ADSL router (at the moment there is no reasonable way to get around it).
1841-1 <-> WAN <-> ADSL Router <-> 1841-2
FE0/1 Private LAN 172.16.1.1
FE0/0 Public IP
Private LAN1 192.168.0.1
FE0/0 LAN1 IP 192.168.0.1
FE0/1 LAN2 IP 172.16.0.1
172.16.1.0-172.16.0.0 require to communicate over the IPSec tunnel.
Could you please advice me on 1) what is the most practical way to set this up with out loosing sanity; and 2) Could you maybe point me to some documentation that deals with this specific scenario?
You can thus give your Cisco router a private IP behind ADSL router and then follow the steps from the knowledge base article above on ADSL modem (if you have same type available).
In addition then, on your Cisco router - you require to add loopback 0 interface and give it public IP of your ADSL router (yes - your adsl router WAN interface and loopback interface on your Cisco router have now the same public IP).
As the last step, on your Cisco router, change tunnel interface: source interface loopback 0 and destination your remote gateway.
I am going to try different modems, many models can actually do this, but the documentation is often unimpressive.
It is possible that there are better ways to do this, if so, please let me know.
If you wish to have more details about the set-up, let me know.
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...