Two fiber optic connections (Problem: both get the same gateway IP-address)

[Thorsten76]

I have two fiber optic connections.
No problem so far, but both PPP dial-ins end up on the same core router.
This has the address 45.155.140.1 as a gateway for PPPoE dial-ins.

This means that both WAN connections get the same "gateway IP-address".
So I cannot use two WAN interfaces on one firewall with the same gateway IP.

This is currently causing problems on the OPNsense firewall because my firewall rules don't work if the gateway IPs are identical. (e.g. when assigning DNS servers via floating rules)
I'm also now having problems with because the routing isn't working correctly.

OPNsense 19" appliance with 4 network ports
WAN1_fiber_private / PPPoE / Gateway IP 45.155.140.1 (on LAN port 3)
WAN2_fiber_business / PPPoE / Gateway IP 45.155.140.1 (on LAN port 4)


The provider (Greenfiber) wrote to me about this:
You terminate both PPP dial-ins on the same core router. This has the address 45.155.140.1 as a gateway for PPPoE dial-ins. The ONT (fiber optic modem) only serves as a Layer2 modem, it does not perform dial-in or anything similar.
I'm not exactly sure if the OPNsense can handle two same WAN gateways - you might have to ask the OPNsense community here.

[mooh]

I'm very interested to learn what the ISP thinks the solution should be.

While I haven't done this myself, it might be possible to use policy routing to force traffic out through one interface or the other. Your interface naming implies that there is private and business data. If one can tell the difference by the source address, that can be used as a policy to force data out the private or business interface.