PfSense behind multiple existing routers

  • Hello,

    Here is my situation, I have inherited from a badly designed infrastructure, that I managed to pull toward the following state :

    • One VDSL Router (Operator: OVH) - could probably be used as bridged mode
    • One SDSL Router (Operator: OBS) - as always with Orange Business Service in france, it's a blackbox, no clue what it can or cannot do + it is linked to a PBX and cannot be moved/removed/touched
    • One 4G Router (Operator: Bouygues) - cannot be used as bridged mode

    a router provides internet to users (VDSL),
    another one allows for remote access to our servers (SDSL),
    and the last one (4G) is used to allow for uploading our backups outside of the office with a decent upload rate that could not be achieved with VDSL or SDSL.

    I would like to aggregate somehow all those links to a single pfsense instance so that I can :

    • Have an automatic failover for our users
    • Have a loadbalancing and/or qos for outgoing traffic

    Can this be done without extensive tweaking of pfsense ? How ? (simple pointers or indications would help me a lot)
    Thank you very much for your input !

  • Netgate Administrator

    Sure, you can have a number of combinations there.

    As long as the specifics of the connections are handled by the other devices pfSense will treat them like 3 Ethernet WAN connections. You can lodd-balance or failover between any or all of them. Policy route specific users to gateway groups. Many combinations are possible.

    If the SDSL connection is for incoming connections then it will need to provide a public IP to pfSense or forward those connections to it.


  • Thank you.

    I assumed the normal way to do it was to have modem-router that could behave as bridged mode, which not all can. Hence my doubts.

    So, if I'm not mistaken, the main thing to do is, for the SDSL router, to define a DMZ, that DMZ being pfsense (for inbound traffic purposes).
    The remaining routers, would keep their existing IPs, and I would have to tell pfSense about those IP's.

    Two of my routers are on the same subnet, could pfSense cope with that ?
    Or would I have to isolate them on independant NICs ?

    Thank you again for your help.
    I'm sorry about the amount of questions, but "trying for myself" would require bringing the office network offline,
    or at least in a degraded state which is not desirable in a production environment.

  • LAYER 8 Global Moderator

    "Two of my routers are on the same subnet"

    You mean the rfc1918 behind them is both say 192.168.1/24?  Can you not change one of them? Even the cheapest of 20$ soho routers allow you to change the IP range it uses on its lan away from the default.

    pfsense is not going to let put 2 interfaces in the same network.  If you can not change one of the networks so you have 3 different rfc1918 address spaces or any combo of rfc1918 and public you would need to create a VIP on the interface on pfsense.  Where your 2 routers lan are in the same L2 network and pfsense wan interface is connected to this L2.

    You can then direct traffic to your different gateways via the VIP ip.

  • Netgate Administrator

    Yes that ^. But it's ugly!

    It relies on those two routers not using the same IP address them selves. So one would need to be on, say, and the other at That way you can set them up as two gateways in pfSense to route to.


  • Thanks,

    To clarify (proper terminology evades me) :
    SDSL is using,
    VDSL is using
    The 4G router is on different network alltogether (and only available to one single server, as the router's firmware doesn't allow anything other than

    What I meant was, that I would prefer to keep the SDSL and VDSL in the same "network" (on 10.10.10.x), simply because both of them would be connected to the pfsense machine with a single physical interface (and probably still accessible to the computers of the network without using pfsense during migration and r&d).

    I'm not sure to understand if it's doable but bad practice, doable and acceptable practice, and not doable at all.

    If necessary, I've found a quad RJ45 ethernet PCIe card on Amazon, if I had to connect each router on a distinct physical interface of the pfsense instance.

  • Netgate Administrator

    I would certainly prefer to see the two routers on separate subnets and interfaces but it should work OK with one as long as they are on different IP addresses, which they are.


  • LAYER 8 Global Moderator

    " if I had to connect each router on a distinct physical interface of the pfsense instance."

    Pfsense is not going to let you create IP in the same network on 2 different interfaces.  Which is why I mentioned you could do it with a vip on 1 if they have to be in the same network.

  • Thanks, I'll go with the quad ethernet card then.

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