Host-firewall-host configuration

The host-firewall-host configuration option for tunnels allows you to create a tunnel between your host and a firewall, then automatically generate the necessary filter rules for correct communication between your host and a host behind the firewall.

The autogenerated filter rules permit all rules between the two non-firewall hosts over the tunnel specified. The default rules—for user datagram protocol (UDP), Authentication Headers (AH), and Encapsulating Security Payload (ESP) headers—should already handle the host to firewall communication. The firewall will have to be configured appropriately to complete the setup. You should use the export file from the tunnel you created to enter the SPI values and keys that the firewall needs.

Figure 1. Host-Firewall-Host
This illustration shows a Host-Firewall-Host configuration. Host A has a tunnel running through a local firewall and out to the internet. Then it goes to Remote Firewall B, and then on to Remote Host C.