pfSense behind another router?

Discussion in 'Software Stuff' started by GCM, May 15, 2016.

  1. GCM

    GCM Active Member

    Aug 24, 2015
    Likes Received:
    Has anyone set up pfSense behind another router?

    I'm looking to utilize pfSense as a DNS server only (for now). However, I seem to be running into a brick wall when trying to get it to do so.

    For now what I've done:

    Disabled the WAN interface
    Enabled the LAN interface

    Set up the DNS resolver
    Set the external DNS (Google DNS) servers in general

    Set my router as my gateway (
    Set static IP on the LAN interface, with the proper subnet.

    I feel like I'm missing something here, do I need to set a static route from my router to pfSense, just to do DNS?
  2. Markus

    Markus Member

    Oct 25, 2015
    Likes Received:
    First of all, what does not work?

    The clients need the information, that they have to use the DNS-Server of the pfSense-Box and not the router's one.
    So I assume you have enabled the DHCP-Server at the router? If yes you have to check if the DNS-Server given to the client is the correct one.

    Linux-Client: cat /etc/resolv.conf
    Windows-Client: ipconfig -all

    If you deactivate the WAN-Interface pfSense should not be able to contact the Google-DNS (depends on the rest of your configuration).
    So check with the Webinterface:

    Can you check these to clarify if there is any configuration missing on your side?
  3. PigLover

    PigLover Moderator

    Jan 26, 2011
    Likes Received:
    Everything on the Internet is "behind another router". The whole darn network is nothing but interconnected routers :)

    Your issue is likely NAT behind another NAT. This can work but requires some care. At a minimum need to be sure that you don't have both routers using the same subnet for their NAT. If the "outer" router is assigning addresses in the subnet then your "inner" router needs to select a different range (perhaps something from the range).

    You said you set your LAN interface "from the proper range". What range did you use?
  4. Zack Hehmann

    Zack Hehmann Member

    Feb 6, 2016
    Likes Received:
    I have done a setup like this for a friend. Did you end up figuring this out?

    I'm more than happy to help you with the config and could assist over a hangout/teamviewer session if you like. Just let me know.

    Sent from my Nexus 6P using Tapatalk
  5. _alex

    _alex Active Member

    Jan 28, 2016
    Likes Received:
    The outer routers LAN is the inner routers (pfsense) WAN and also the default-gateway for pfsense.

    The inner routers LAN (OPT if applicable) need different subnet/s and/or own VLAN's. You then need rules to allow LAN/OPT <-> WAN Access via pfsense, and the clients on LAN/OPT need to use pfsense IP on these networks their default-gateway.

    For LAN auto-generated rules should be fine ...
  6. ReturnedSword

    ReturnedSword Active Member

    Jun 15, 2018
    Likes Received:
    @morris88 Did you just make an account and necro a thread to plug your affiliate link site? Not to be rude, but your comment has nothing to do with this thread.
  7. epicurean

    epicurean Member

    Sep 29, 2014
    Likes Received:
    I also wanted to put a unifi router(eg. USG) either in front or behind pfsense , so that the rest of the nice unifi stats get filled up in their interface. I do have a few unifi switches and access points. perhaps just using the USG to serve as a DHCP server and everything else done by pfsense. So far, I have not found anything reliable or something I can comprehend.
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