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

    Available range in pfsense not right

    DHCP and DNS
    7
    13
    2.6k
    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.
    • DerelictD
      Derelict LAYER 8 Netgate
      last edited by

      Correct that in the interface configuration.

      Chattanooga, Tennessee, USA
      A comprehensive network diagram is worth 10,000 words and 15 conference calls.
      DO NOT set a source address/port in a port forward or firewall rule unless you KNOW you need it!
      Do Not Chat For Help! NO_WAN_EGRESS(TM)

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

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

          1 Reply Last reply Reply Quote 0
          • NogBadTheBadN
            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
              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 24.11 | Lab VMs 2.7.2, 24.11

              1 Reply Last reply Reply Quote 0
              • KOMK
                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
                  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
                    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
                      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
                        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
                          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.