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

    Available range in pfsense not right

    Scheduled Pinned Locked Moved DHCP and DNS
    13 Posts 7 Posters 2.8k Views
    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.
    • NogBadTheBadN Offline
      NogBadTheBad
      last edited by

      Just tried it with an unused interface the calculated values seem wrong with a subnet mask of /31 or /32.

      172.16.99.1/32 on OPT4 :-

      Subnet 172.16.99.1
      Subnet mask 255.255.255.255
      Available range 172.16.99.2 - 172.16.99.0

      172.16.99.1/31 on OPT4 :-

      Subnet 172.16.99.0
      Subnet mask 255.255.255.254
      Available range 172.16.99.1 - 172.16.99.0

      172.16.99.1/30 on OPT4 :-

      Subnet 172.16.99.0
      Subnet mask 255.255.255.252
      Available range 172.16.99.1 - 172.16.99.2

      Andy

      1 x Netgate SG-4860 - 3 x Linksys LGS308P - 1 x Aruba InstantOn AP22

      1 Reply Last reply Reply Quote 0
      • D Offline
        doktornotor Banned
        last edited by

        Ugh. /31 or /32 is NOT usable for DHCP. PEBKAC.

        1 Reply Last reply Reply Quote 0
        • NogBadTheBadN Offline
          NogBadTheBad
          last edited by

          @doktornotor:

          Ugh. /31 or /32 is NOT usable for DHCP. PEBKAC.

          I know it's not usable  ;D

          Andy

          1 x Netgate SG-4860 - 3 x Linksys LGS308P - 1 x Aruba InstantOn AP22

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

            Welcome back dok!  That is the wit I am talking about ;)

            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
            SG-4860 25.07.1 | Lab VMs 2.8, 25.07.1

            1 Reply Last reply Reply Quote 0
            • KOMK Offline
              KOM
              last edited by

              Ugh. /31 or /32 is NOT usable for DHCP. PEBKAC.

              JHC I think I've seen a ghost  :o

              1 Reply Last reply Reply Quote 0
              • D Offline
                doktornotor Banned
                last edited by

                @NogBadTheBad:

                @doktornotor:

                Ugh. /31 or /32 is NOT usable for DHCP. PEBKAC.

                I know it's not usable  ;D

                Doc, it hurts when I do this… So don't do that. ;D

                Eh, I mean, by all means submit a pull request to fix this cosmetic issue with "miscalculation" (not that I could imagine how'd you fix it beyond completely disabling the enable DHCP server checkbox until people fix their subnet, which in turn would only produce another batch of posts about "cannot enable DHCP server no matter what… t3h bug!!!" But why'd anyone knowingly set up a point-to-point subnet (let alone a single host) and try to run DHCP on it?  ???

                Now, will someone fix my DHCP relay?  :'(

                1 Reply Last reply Reply Quote 0
                • JKnottJ Offline
                  JKnott
                  last edited by

                  Ugh. /31 or /32 is NOT usable for DHCP. PEBKAC.

                  DHCP requires use of the broadcast address,which means the smallest usable subnet is a /30, which provides network address, broadcast address and 2 host addresses.  One of those 2 has to be for the server or agent.  A /31 provides only 2 host addresses and is used for point to point links.  A /32 means only the interface and nothing beyond it.

                  PfSense running on Qotom mini PC
                  i5 CPU, 4 GB memory, 32 GB SSD & 4 Intel Gb Ethernet ports.
                  UniFi AC-Lite access point

                  I haven't lost my mind. It's around here...somewhere...

                  1 Reply Last reply Reply Quote 0
                  • NogBadTheBadN Offline
                    NogBadTheBad
                    last edited by

                    LOL I was just pointing out the calculation was wrong, I wasn't even the OP.

                    All my subnets are /24 or /64  :)

                    Andy

                    1 x Netgate SG-4860 - 3 x Linksys LGS308P - 1 x Aruba InstantOn AP22

                    1 Reply Last reply Reply Quote 0
                    • D Offline
                      doktornotor Banned
                      last edited by

                      Yeah, it's wrong because it makes no sense. See https://redmine.pfsense.org/issues/6930

                      1 Reply Last reply Reply Quote 0
                      • S Offline
                        sd_read
                        last edited by

                        Thank you for your help.

                        That fixed my problem.

                        1 Reply Last reply Reply Quote 0
                        • First post
                          Last post
                        Copyright 2025 Rubicon Communications LLC (Netgate). All rights reserved.