In this article we will establish a site-to-site VPN connection between an ISA 2006 Firewall and a Cisco Router.
One site is using ISA 2006 Firewall Standard Edition installed on Windows 2003 R2 Standard SP2. The network behind the ISA 2006 Firewall is 192.168.10.0/24.
The other site is using a Cisco 3620 router. If you wonder about the IOS type and version, it’s running IP/FW/IDS PLUS IPSEC 3DES(c3620-ik9o3s-mz), version 12.2(40). OK, the version is old but it will not matter since it supports 3DES. Also since it has the IOS firewall on it we can setup it as a firewall too. If you have newer versions of IOS, you can benefit from the enhanced firewall support. It’s all about the amount of money you have to spent(or about the router you have bought). The network behind the 3620 router is 192.168.40.0/24.