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    Strange DHCP issue. Assigned /8 instead /24 on Linux devices.

    Scheduled Pinned Locked Moved DHCP and DNS
    dhcp 8 24
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    • L
      lazy @kiokoman
      last edited by lazy

      @kiokoman today i checked all once again, and i see that the 255.0.0.0 mask was assign to windows machines too, but in settings of DHCP server (and lan interface too) installed a 255.255.255.0 mask... How that work?

      2020-02-02_20-44-37.png

      1 Reply Last reply Reply Quote 0
      • kiokomanK
        kiokoman LAYER 8
        last edited by

        if you can plug something directly to the lan of pfsense to see if it works, maybe there is something wrong on the switch

        ̿' ̿'\̵͇̿̿\з=(◕_◕)=ε/̵͇̿̿/'̿'̿ ̿
        Please do not use chat/PM to ask for help
        we must focus on silencing this @guest character. we must make up lies and alter the copyrights !
        Don't forget to Upvote with the 👍 button for any post you find to be helpful.

        L 1 Reply Last reply Reply Quote 1
        • DerelictD
          Derelict LAYER 8 Netgate
          last edited by

          You probably have another DHCP server on your network.

          Packet capture the port 67 traffic and wireshark will tell you exactly what DHCP is doing. Pay close attention to what MAC address is sending what.

          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)

          L 1 Reply Last reply Reply Quote 1
          • L
            lazy @kiokoman
            last edited by

            @kiokoman i'm tied, nothing changes...

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            • L
              lazy @Derelict
              last edited by

              @Derelict said in Strange DHCP issue. Assigned /8 instead /24 on Linux devices.:

              Packet capture the port 67 traffic and wireshark will tell you exactly what DHCP is doing.

              Tried it too. PFSense is only the one dhcp server in the my network... :(

              1 Reply Last reply Reply Quote 0
              • chpalmerC
                chpalmer
                last edited by

                You don't have anything configured under "Additional BOOTP/DHCP Options" do you?

                Triggering snowflakes one by one..
                Intel(R) Core(TM) i5-4590T CPU @ 2.00GHz on an M400 WG box.

                1 Reply Last reply Reply Quote 1
                • DerelictD
                  Derelict LAYER 8 Netgate
                  last edited by

                  Post the packet capture of a complete DHCP exchange. If the DHCP server is sending /24 and the clients are setting /8 there is nothing the DHCP server can do about it.

                  Also post the contents of /var/dhcpd/etc/dhcpd.conf from the pfSense node.

                  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)

                  L 1 Reply Last reply Reply Quote 1
                  • L
                    lazy @Derelict
                    last edited by lazy

                    @Derelict
                    wireshark capture: (deleted)

                    dhcp.conf (deleted)

                    I cleared private data from dhcp.conf

                    @chpalmer nothing in Additional settings.

                    JKnottJ 1 Reply Last reply Reply Quote 0
                    • chpalmerC
                      chpalmer
                      last edited by

                      Go back into the settings of your padavan units and verify that the DHCP servers are truly turned off.

                      Go into your switches and verify that the DCHP servers are truly turned off.

                      Triggering snowflakes one by one..
                      Intel(R) Core(TM) i5-4590T CPU @ 2.00GHz on an M400 WG box.

                      L 1 Reply Last reply Reply Quote 1
                      • L
                        lazy @chpalmer
                        last edited by

                        @chpalmer shure, it's already done...
                        No active DHCP servers on my padavan units (configured as access points), switches (it's not have a dhcp server options), and on my synology unit too...

                        chpalmerC 1 Reply Last reply Reply Quote 0
                        • chpalmerC
                          chpalmer @lazy
                          last edited by

                          @lazy

                          I confused the DGS1100 and the DGS1510 which does have an available DHCP server..

                          On the Padavan there is the option of Static IP assignment.. Is that also off?

                          Are all your Linux devices you are testing wireless?

                          Triggering snowflakes one by one..
                          Intel(R) Core(TM) i5-4590T CPU @ 2.00GHz on an M400 WG box.

                          L 1 Reply Last reply Reply Quote 1
                          • L
                            lazy @chpalmer
                            last edited by

                            @chpalmer said in Strange DHCP issue. Assigned /8 instead /24 on Linux devices.:

                            all your Linux devices you are testing wireless?

                            2020-02-02_23-10-18.png
                            It's not have anything about DHCP or address reservations. Configured as access point. Another padavan unit configured the same.

                            I tested wireless and wired devices, nothing changes, but today i see that the windows device assigned 255.0.0.0 too. So, it's not a linux problem...

                            1 Reply Last reply Reply Quote 0
                            • chpalmerC
                              chpalmer
                              last edited by

                              Quick test.. Unplug everything from your pfSense router. Or just turn it off.

                              Reboot one of the devices that is getting wrong info. See if it gets an address.

                              Triggering snowflakes one by one..
                              Intel(R) Core(TM) i5-4590T CPU @ 2.00GHz on an M400 WG box.

                              L 1 Reply Last reply Reply Quote 1
                              • L
                                lazy @chpalmer
                                last edited by

                                @chpalmer tried it before, and it's not help, but, i will try it tomorrow again...
                                Pfsense unit not in my room, and for now i can't access it phisicaly.

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

                                  @lazy said in Strange DHCP issue. Assigned /8 instead /24 on Linux devices.:

                                  wireshark capture: bootpwireshark.pcapng

                                  I don't see option 1, the subnet mask in there.

                                  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...

                                  L 1 Reply Last reply Reply Quote 1
                                  • L
                                    lazy @JKnott
                                    last edited by

                                    This post is deleted!
                                    1 Reply Last reply Reply Quote 0
                                    • L
                                      lazy
                                      last edited by lazy

                                      Sorry guys, totally my bad :(
                                      I'm not fully understand how works Additional DHCP settings in pfsense...
                                      At very strange situation, I have option "1" in Additional DHCP settings with parameter "text", and under this table was button "add", I think I need to push this button for take effect....
                                      I'm totally don't know how "1" was typed here, maybe my mistake (missclick), maybe something else...
                                      I removed "1" from the option, and then the correct mask was successfully assigned to my devices...

                                      I really want to make a death facepalm to myself.

                                      @chpalmer you was right!

                                      @JKnott thank you, I think I don't take attention to this parameter without your comment.

                                      Also, I deleted my dump and other files that may have my personal data.

                                      Thanks to all. This theme may be closed, and marked as solved.

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

                                        @lazy said in Strange DHCP issue. Assigned /8 instead /24 on Linux devices.:

                                        When I connect any Linux based device (Debian, Ubuntu, Synology, Android, etc), I have assign a wrong DHCP settings with Network mask 255.0.0.0, and can't use Network on some devices (Android and Synology works, but any of Linux distro won't works).

                                        One thing on this, back in the classfull subnet days, a 10.0.0.0 network was a class A network, with a /8 subnet mask. It appears Linux is following that convention. I have no idea why other devices are doing otherwise.

                                        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...

                                        L 1 Reply Last reply Reply Quote 0
                                        • L
                                          lazy @JKnott
                                          last edited by

                                          @JKnott I have no idea too...
                                          All Linux devices was followed this rules, but windows devices are followed too, but not all.
                                          I have 3 Windows 10 devices with assigned /8 in this situation, and all other devices was assigned /24 in this situation.
                                          But now all works well, I fixed this issue by removing Aditional DHCP settings, as i told before.

                                          Thanks again!

                                          1 Reply Last reply Reply Quote 0
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