Navigation

    Netgate Discussion Forum
    • Register
    • Login
    • Search
    • Categories
    • Recent
    • Tags
    • Popular
    • Users
    • Search

    DNS randomly returns switch ip as client ip ??

    DHCP and DNS
    2
    3
    234
    Loading More Posts
    • Oldest to Newest
    • Newest to Oldest
    • Most Votes
    Reply
    • Reply as topic
    Log in to reply
    This topic has been deleted. Only users with topic management privileges can see it.
    • P
      peoples last edited by

      Hey,

      have the following strange behaviour after update from 2.3.3 to 2.4.2-p1 . PFsense DHCP Server is serving IP with DNS Resolver enabled.

      Linux environment (Clients and Server).
      Sometimes when i try to ping a client name from a random server, pfsense DNS Resolver returns the IP of my core switche instead of client IP.  For me this seems to appear randomly. DHCP Lease in PFsense shows right ip. After rebooting client, DNS for this client works again.

      Had no issue before update to 2.4.2-p1 .. Does someone have an idea whats wrong here ?

      Thanks

      1 Reply Last reply Reply Quote 0
      • P
        peoples last edited by

        i guess dns resolver has some internal cache … is there maybe a TTL for cache entries ? Can this be a reason ?

        1 Reply Last reply Reply Quote 0
        • johnpoz
          johnpoz LAYER 8 Global Moderator last edited by

          DNS without a TTL would be nuts ;)

          Yes the default ttl for a host override or static reservation would be 3600 seconds or 1 hour.  I do not have normal dhcp clients register but would assume they would be the same.. If a client looks up some it would get that ttl..  It would not ask dns again for that fqdn until the ttl expires in the local clients cache.

          Unless you flush the clients local cache..

          windows can do this with

          ipconfig /flushdns

          An intelligent man is sometimes forced to be drunk to spend time with his fools
          If you get confused: Listen to the Music Play
          Please don't Chat/PM me for help, unless mod related
          2440 2.4.5p1 | 2x 3100 2.4.4p3 | 2x 3100 22.01 | 4860 22.05

          1 Reply Last reply Reply Quote 0
          • First post
            Last post