Routing VIP traffic through VPN tunnel

We have a scenario we are trying to test. We have a webserver setup at one location (we’re calling it Downtown), network subnet of 192.168.0.0/24. We have another subnet at the same physical location called the Downtown Office, 192.168.4.0/24. There’s a second physical location (we’re calling remote, 192.168.5.0/24) that has a VPN tunnel established to the Downtown firewall. Finally, we have internet we’re calling EPB will some fake WAN addresses (10.100.100.0/24) along with one Public PC to test the VIP to the webserver at the Downtown location.

In this setup, everything works as expected, the webserver can be accessed by all parties, no problems.

The issue comes when we attempt to move the webserver to live under the Remote firewall.

Before Move

After the move, the intention is to keep the VIP running at the Downtown firewall and route the traffic through the VPN tunnel into the Server network at the Remote firewall.

As far as we can tell, we have the routes, rules, and tunnels setup properly to allow the traffic, but the Public PC refuses to bring up the site from the Downtown firewall WAN IP. Everything else works as expected from the Remote and Downtown clients.

After Move

The idea here is we are testing the thought of moving a server environment before making any outside changes to help ease the pain of moving an entire server environment.

We intend to eventually move the DNS entries and so forth to point to the new firewall eventually, but it would encompass quite a bit and we are trying to spread out the changes and reduce downtime.

If this is possible, I’d like to know what we are missing.

Try NAT-in the Public-PC on the Downtown-FW with an IP that isnt used from one of the networks that are being used as selectors/routed through the VPN.

Downtown-FW

srcintf WAN to dstintf VPN ; srcip IP to dstip vIP ; NAT enabled ( here the vIP should be configured to have any as interface or VPN )

Remote-FW

srcintf VPN to dstintf LAN ; srcip NAT-IP to dstip Webserver vIP

To anyone wanting this to work

On the Downtown firewall we’ve:

  • setup an IP Pool with a single address (192.168.166.1)
  • setup a VIP with “Any” as the interface, external IP of 10.100.100.1, internal IP of 192.168.5.2, and port 80 mapped to port 80
  • setup a rule from WAN port to the VPN tunnel, from all source to the above created VIP, and NAT’ed with a dynamic pool using the 192.168.166.1 address
  • set the 192.168.166.1 address to be routed through the tunnel to the remote firewall

On the Remote firewall we’ve:

  • Setup a rule from the VPN tunnel to the newly created server network, from the 192.168.166.1 address to the Server Range, and whatever services you want

It seems the only downside (other than being massively inefficient) is that

  1. you will need to create another set of VIP’s
  2. Modify your incoming rules to use the dynamic pool

But it did work, thank you!!