DNS forward issue

  • Hello,

    I have a strange issue with my dns resolver

    My setup is as follow :

    Servers interface --> Active directory / DNS forward to PFSENSE -> PFSENSE DNS Resolver forward to my ISP DNS.

    in this setup, every server has DNS resolver OK. But there will be a moment where PFSENSE stops forwarding to my isp, permanently, until i reboot pfsense.
    I use the DNS resolver, not the forwarder, and in the resolver i use the forwarder mode.
    i listen on all interface, and out to all. I just tried to listen to lan/localhost and out to carp wan, with no more luck

    I can see when having the issue:

    • no DNS Block in pfsense
    • dns requests states from servers to my AD (ok)
    • Dns requests states from the AD to the pfsense lan interface (ok). The states are MULTIPLE:MULTIPLE, with traffic ko in both ways
    • no dns request to the isp dns ip (ko)
    • nslookup google.fr on my pfsense LAN ip (master or slave) or on the CARP ip, from one of my server : KO
    • nslookup google.FR on my isp ip from one of my server : OK
    • I have NO stats in the DNS resolver Status on the primary pfsense (nothing written in cache speed and cache stats), and i have some stats on the slave .

    I have tried to :

    • restart the DNS resolver, still having the issue
    • dns lookup through the webui : I have an answer from my ISP, it is ok (my pfsense is set up to use the DNS RESOLVER itself)
    • read the resolver log : i do not see anything i ask in my log (ie : nslookup google.com --> no google.com found in log). I only see the requests done through the ui

    The only way to make it ok, is to restart the pfsense.

    Please note, i have an AD in 2 node, and a CARP Pfsense setup. My dns settings are default, except the forward mode ticked.

    would someone have an idea to point me something to investigate ?

    appreciate your time,


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