topic Re: Tunnel Interface IP Address in General Topics

Tunnel Interface IP Address

mario11584 — Tue, 02 Apr 2013 22:56:33 GMT

Can somebody explain to me the need for the tunnel interface IP address? Apparently a VPN tunnel requires a tunnel interface configured with an IP address when using dynamic routing. Is that a dynamic gateway the PA is connecting to or the PA is using a dynamic IP? Also, does this IP address have to live on the same network as the local network? During testing I've used a completely random IP address and the tunnel has still worked. Maybe it wasn't even being used though because I had a lan to lan with static IPs.

I couldn't find any good details on this anywhere. A good explanation from the experts would be appreciated. __

Re: Tunnel Interface IP Address

goku123 — Wed, 03 Apr 2013 12:50:07 GMT

As you mentioned, sometimes, there may be a need to run dynamic routing over a VPN, most commonly OSPF. In that case OSPF neighbor ship can be formed over the VPN (ie the PA tunnel interface and the remote end point basically send their OSPF messages over the VPN). The tunnel interface IP will be used for this.

(ii) You can also use a feature called tunnel monitoring on the PA device. Using tunnel monitoring, you can send ping packets over the VPN to monitor a device/IP on the remote network and if that end point goes down take some action. The PA device will use the tunnel interface's IP to source the ping packets.

Re: Tunnel Interface IP Address

mario11584 — Wed, 03 Apr 2013 14:43:27 GMT

Thank you for the clarification.