0

I have a static WAN IP address (in the example 77.88.99.166) that is provided by a DSL modem that also has a static IP address (77.88.99.165). The modem interfaces with a firewall/NAT router (green) that also provides VPN connectivity to all clients. I would like to introduce another pfSense based firewall/NAT router (red) to extend my network, however, I can't change the configuration of the old green router in any way.

Is there a way to introduce this new red router (with IP adress 77.88.99.166) while keeping the green router (also listening on 77.88.99.166)? Of course the old green router would be behind NAT which is fine. The problem I see is, that the pfSense router would have an interface with IP .166 and on another interface the same .166 IP.

Old and desired setup

schneida
  • 339
  • 1
  • 4
  • 15
  • I just need something to be clear here.. Your current router have the IP 77.88.99.166 and a default gateway of ?.?.?.? - Then you have a second IP that is not in use now that is 77.88.99.165 - Is that the case here? Or is the gateway 77.88.99.165 ? – Frederik Dec 05 '15 at 23:37
  • Will the server have two interfaces, to red and green routers? Currently all 3 are connected on one line which is a little confusing. Devices sharing IP addresses is generally not going to work. Unless they are intended to be one logical router with a redundancy protocol, which doesn't look like is the case here. You can give the red router a different IP address. Set a route for 77.88.99.166 down the correct interface. – John Mahowald Dec 06 '15 at 07:27
  • @FrederikNielsen 77.88.99.165 is the gateway (the ip address of the modem), so there is only one public IP address! – schneida Dec 06 '15 at 19:29
  • @JohnMahowald yes the server would have to interfaces to the red and green router. I know that sharing IP addresses is not a good thing, however I don't see another option without changing the IP of the green router (which I can't)... – schneida Dec 06 '15 at 19:32
  • For now, I worked around the issue by splitting the setup into two machines. The red router is assigned 77.88.99.166 and gw 77.88.99.165 on the WAN side and 10.10.20.253 on the LAN side. On a linux server with two interfaces, one interface is on the 10.10.20.x subnet and the other has the static IP 77.88.99.165 connected to the green router. The linux server routes all traffic between those interfaces with gateway 10.10.20.253, whereas all other clients still have 10.10.20.254 as default gw. Is there a way to combine this setup into the pfSense router? – schneida Dec 06 '15 at 20:37

1 Answers1

0

Your only option in this case would be to setup the green router in bridge-mode and only use the pfsense router for both networks. You do however mention that it's not an option so in your case I don't see any good way of doing it.

The perfect setup would be something like:

WAN -> Modem -> ISP Router (bridge mode) -> pfsense -> 10.10.20.X network
                                                    -> New network
Frederik
  • 3,293
  • 3
  • 30
  • 46
  • Hm so you are saying there is no way to do it? I have added comment showing a way to do it with to machines, do you think this could be integrated into the red pfSense router? – schneida Dec 06 '15 at 20:38