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

    Strange address Shown in the dhcp leases

    Scheduled Pinned Locked Moved General pfSense Questions
    57 Posts 12 Posters 14.1k 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.
    • F Offline
      firefox
      last edited by

      i dont have VM
      and i mean the MAC
      and the status  cltt 3

      what is  cltt 3    ??

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

        prob got some kind of corruption in the leases db.. just delete it..

        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 | Lab VMs 2.8, 25.07

        1 Reply Last reply Reply Quote 0
        • F Offline
          firefox
          last edited by

          It come back
          this time Listed cltt 5 not 3

          Could it be that someone is trying to get in to the network
          Wirelessly ??

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

            Why don't you look in the actual file for what it shows for the end date, and see what we have..

            example
            [2.2.2-RELEASE][root@pfSense.local.lan]/var/dhcpd/var/db: cat dhcpd.leases

            lease 192.168.2.216 {
              starts 6 2015/06/13 12:04:00;
              ends 3 2015/06/17 12:04:00;
              cltt 6 2015/06/13 12:04:00;
              binding state active;
              next binding state free;
              rewind binding state free;
              hardware ethernet ac:fd:ec:62:34:97;
              uid "\001\254\375\354b4\227";
              client-hostname "Johns-Phone";

            cltt stands for Client Last Transaction Time, not sure why its showing that vs the end date?  I would also track down what device it is, that is clearly an ODD mac..

            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 | Lab VMs 2.8, 25.07

            1 Reply Last reply Reply Quote 0
            • F Offline
              firefox
              last edited by

              how do i see this file

              i did ssh to the Machine (Reminds me person of interest)
              and Paste this /var/dhcpd/var/db: cat dhcpd.leases

              i got this
              /var/dhcpd/var/db:: Too many arguments.

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

                i did ssh to the Machine (Reminds me person of interest)
                and Paste this /var/dhcpd/var/db: cat dhcpd.leases

                try:
                cd /var/dhcpd/var/db
                cat dhcpd.leases

                or:
                cat /var/dhcpd/var/db/dhcpd.leases

                or:

                less /var/dhcpd/var/db/dhcpd.leases

                These are basic FreeBSD commands.
                There are many primers/HowTos on the commands and how/when to use them available with a quick Google search.

                -jfp

                1 Reply Last reply Reply Quote 0
                • F Offline
                  firefox
                  last edited by

                  this is what i got

                  # The format of this file is documented in the dhcpd.leases(5) manual page.
                  # This lease file was written by isc-dhcp-4.2.6
                  
                  lease 192.168.0.30 {
                    starts 1 2015/05/25 04:04:19;
                    ends 1 2015/05/25 06:04:19;
                    tstp 1 2015/05/25 06:04:19;
                    cltt 1 2015/05/25 04:04:19;
                    binding state free;
                    hardware ethernet 00:1c:85:0d:1d:68;
                    uid "\001\000\034\205\015\035h";
                  }
                  lease 192.168.0.31 {
                    starts 3 2015/05/27 12:43:26;
                    ends 3 2015/05/27 14:43:26;
                    tstp 3 2015/05/27 14:43:26;
                    cltt 3 2015/05/27 12:43:26;
                    binding state free;
                    hardware ethernet 54:35:30:b1:da:f5;
                    uid "\001T50\261\332\365";
                  }
                  lease 192.168.0.32 {
                    starts 0 2015/05/31 19:16:46;
                    ends 0 2015/05/31 21:16:46;
                    tstp 0 2015/05/31 21:16:46;
                    cltt 0 2015/05/31 19:16:46;
                    binding state free;
                    hardware ethernet 94:35:0a:23:07:f3;
                    uid "\001\2245\012#\007\363";
                  }
                  lease 192.168.0.33 {
                    starts 4 2015/06/04 06:42:41;
                    ends 5 2015/06/05 06:42:41;
                    tstp 5 2015/06/05 06:42:41;
                    cltt 4 2015/06/04 06:42:41;
                    binding state free;
                    hardware ethernet 0c:74:c2:e1:78:f9;
                    uid "\001\014t\302\341x\371";
                  }
                  lease 192.168.0.36 {
                    starts 4 2015/06/11 15:39:16;
                    ends 4 2015/06/11 17:39:16;
                    tstp 4 2015/06/11 17:39:16;
                    cltt 4 2015/06/11 15:39:16;
                    binding state free;
                    hardware ethernet f8:d1:11:16:4b:d9;
                  }
                  lease 192.168.0.35 {
                    starts 4 2015/06/11 15:41:11;
                    ends 4 2015/06/11 17:41:11;
                    tstp 4 2015/06/11 17:41:11;
                    cltt 4 2015/06/11 15:41:11;
                    binding state free;
                    hardware ethernet 00:1b:38:46:27:6b;
                  }
                  lease 192.168.0.37 {
                    starts 4 2015/06/11 15:41:19;
                    ends 4 2015/06/11 17:41:19;
                    tstp 4 2015/06/11 17:41:19;
                    cltt 4 2015/06/11 15:41:19;
                    binding state free;
                    hardware ethernet 00:1c:bf:11:dc:62;
                  }
                  lease 192.168.0.42 {
                    starts 5 2015/06/12 08:38:46;
                    ends 5 2015/06/12 10:38:46;
                    tstp 5 2015/06/12 10:38:46;
                    cltt 5 2015/06/12 08:38:46;
                    binding state free;
                    hardware ethernet 94:35:0a:23:07:f3;
                    uid "\001\2245\012#\007\363";
                  }
                  server-duid "\000\001\000\001\034c\215 \000\002\263\013\253.";
                  
                  
                  1 Reply Last reply Reply Quote 0
                  • H Offline
                    hda
                    last edited by

                    @firefox:

                    Could it be that someone is trying to get in to the network. Wirelessly ??

                    If you are suspicious about (wireless) connections, then do ACL, explicitly allow MAC addresses (therefore deny the undefined) in your AP.

                    1 Reply Last reply Reply Quote 0
                    • F Offline
                      firefox
                      last edited by

                      what is ACL ?

                      1 Reply Last reply Reply Quote 0
                      • H Offline
                        hda
                        last edited by

                        Access Control List(s)

                        In pfSense have look at Services: DHCP server [MAC Address Control]

                        1 Reply Last reply Reply Quote 0
                        • F Offline
                          firefox
                          last edited by

                          @johnpoz:

                          Why don't you look in the actual file for what it shows for the end date, and see what we have..

                          example
                          [2.2.2-RELEASE][root@pfSense.local.lan]/var/dhcpd/var/db: cat dhcpd.leases

                          lease 192.168.2.216 {
                            starts 6 2015/06/13 12:04:00;
                            ends 3 2015/06/17 12:04:00;
                            cltt 6 2015/06/13 12:04:00;
                            binding state active;
                            next binding state free;
                            rewind binding state free;
                            hardware ethernet ac:fd:ec:62:34:97;
                            uid "\001\254\375\354b4\227";
                            client-hostname "Johns-Phone";

                          cltt stands for Client Last Transaction Time, not sure why its showing that vs the end date?  I would also track down what device it is, that is clearly an ODD mac..

                          Where the last line ```
                          client-hostname "Johns-Phone";

                          
                          It is not registered anything in the output of the command (in my computer)
                          
                          and now it is cltt 6
                          
                          

                          lease 192.168.0.43 {
                            starts 6 2015/06/13 21:31:09;
                            ends never;
                            cltt 6 2015/06/13 21:31:09;
                            binding state active;
                            next binding state free;
                            rewind binding state free;
                            hardware ethernet 00🆎00:00:00:00;

                          
                          How exactly do I use with this ACL option
                          
                          I have to enroll all Mac addresses of all computers on the network
                          One by one comma separated
                          
                          it says partial MAC addresses
                          Which part ?
                          1 Reply Last reply Reply Quote 0
                          • M Offline
                            motionthings
                            last edited by

                            edit3
                            My post was about wireless security, and did not belong here.
                            I'll not be offended if it gets deleted. http://pastebin.com/QaGHXbU4
                            /edit 3

                            edit2
                            Looks like @cmb has a really good answer. Thanks :-)
                            /edit2

                            Intel Core i3, 8GB RAM, 2x Intel Gigabit NIC's.
                            CURRENT network: https://cacoo.com/diagrams/1Fh6EcMdZLjGq3zj
                            Planned network: https://cacoo.com/diagrams/y2rMw37kzlzcHzZy
                            Read BOFH (Bastard Operator From Hell): http://bofh.ntk.net/BOFH/index.php

                            1 Reply Last reply Reply Quote 0
                            • H Offline
                              hda
                              last edited by

                              @firefox:

                              …
                              it says partial MAC addresses
                              Which part ?

                              http://www.gcstech.net/macvendor/index.php?node=macsea

                              1 Reply Last reply Reply Quote 0
                              • C Offline
                                cmb
                                last edited by

                                That's a BOOTP lease, which is why it looks weird.

                                Hostnames are only there where the client sends one. It not having one isn't unusual, especially for the types of devices that do BOOTP.

                                There are very limited devices that use BOOTP. Generally they're very old (1990s era printers for instance), or atypical embedded devices. It could be some broken device as well.

                                It seems to be a semi-active device, or at least your time of last contact (cltt) seems to update. If you have a managed switch, try tracking down that MAC address' port and see what's plugged into it. If you don't have a managed switch it'll be harder to track down, though not too difficult if you have a small network. Unplug most things, see if it's still updating. Add things back one by one. See when that comes back. Or just try reaching the device to see what it's running. A nmap scan with OS identification enabled might be telling.

                                1 Reply Last reply Reply Quote 0
                                • C Offline
                                  cmb
                                  last edited by

                                  @Jailer:

                                  checking now but even if it is why would it be set to never expire?

                                  BOOTP leases never expire.

                                  1 Reply Last reply Reply Quote 0
                                  • C Offline
                                    cmb
                                    last edited by

                                    That MAC seems to be something a number of other people have seen pulling BOOTP leases, though at a glance through Google results I don't see anyone who found the source of it. Might be worthwhile to dig through those results more closely.
                                    https://www.google.com/webhp?q=%2200🆎00:00:00:00%22

                                    1 Reply Last reply Reply Quote 0
                                    • F Offline
                                      firefox
                                      last edited by

                                      I know
                                      Already encountered this once
                                      Last time i  simply blocked the address

                                      This time I wanted to know where it came from

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

                                        well track it down – its clearly on your network..

                                        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 | Lab VMs 2.8, 25.07

                                        1 Reply Last reply Reply Quote 0
                                        • F Offline
                                          firefox
                                          last edited by

                                          I've checked
                                          No device in my network
                                          Have such address

                                          That's why I ask

                                          I blocked it again
                                          As before

                                          1 Reply Last reply Reply Quote 0
                                          • JailerJ Offline
                                            Jailer
                                            last edited by

                                            Yeah it's definitely not a device on my network, this is my home network and every device is accounted for.

                                            Could it possibly be my Dlink router that I'm using as an AP? DHCP is turned off on the router but the wireless does occasionally quit working, especially when it gets warmer out, requiring a power cycle to restore it.

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