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

    Request for dhcp from strange address?

    Scheduled Pinned Locked Moved DHCP and DNS
    39 Posts 6 Posters 5.8k 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.
    • JKnottJ Offline
      JKnott
      last edited by

      Given that the Internet started as a Dept of Defense research project, a lot of addresses were "owned" by the DoD.  When it first started, the 'net was used only by military contractors and researchers, including some universities.

      https://en.wikipedia.org/wiki/History_of_the_Internet

      PfSense running on Qotom mini PC
      i5 CPU, 4 GB memory, 32 GB SSD & 4 Intel 1 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
      • J Offline
        JonH
        last edited by

        I would think that ARIN WHOIS data is relatively up to date.  Maybe I expect too much ::)

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

          Hmmm…

          Whatismyipaddress.com shows it's DoD, located in Utah.  Maybe it has something to do with Area 51.  ;-)

          https://en.wikipedia.org/wiki/Dugway_Proving_Ground#UFO_speculation

          PfSense running on Qotom mini PC
          i5 CPU, 4 GB memory, 32 GB SSD & 4 Intel 1 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
          • johnpozJ Offline
            johnpoz LAYER 8 Global Moderator
            last edited by

            Area 51 is in Nevada ;)  Groom Lake!

            Yeah ARIN is pretty up to date.. Not sure they would have a wrong listing for 30 address..  Are you saying you got your dhcp IP from this IP address??  I am confused on what this address has to do with anything to be honest?  Or what does it matter?  Maybe the dod uses your same ISP??  And they are running multiple layer 3 networks on the same layer 2 ;)

            What that looks like is a dhcpack.. So your saying that is what is giving you your IP??  Then either your ISP is the DOD ;)  Or what is more likely is they are using IPs that are not theirs because they don't think anyone will be talking to those IPs..  While its BAD practice, it is common practice..  Again its BAD practice.. but happens more than you think.. Companies to lazy to do proper IPAM or subnetting or natting when required..  Hey lets grab these /8's that are owned by DOD - nobody is going to be going there ;)

            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 2.8.1, 25.07.1

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

              Area 51 is in Nevada ;)  Groom Lake!

              From the article "[Dugway is] the new Area 51. And probably the new military spaceport.".  ;)

              Or what is more likely is they are using IPs that are not theirs because they don't think anyone will be talking to those IPs..

              My cell carrier did that prior to switching over to IPv6.  I'd get an address in the 25 block, IIRC, which NATed to the 24 block.  Now my phone is IPv6 only and uses 464XLAT to provide IPv4 access.

              https://en.wikipedia.org/wiki/IPv6_transition_mechanism#464XLAT

              PfSense running on Qotom mini PC
              i5 CPU, 4 GB memory, 32 GB SSD & 4 Intel 1 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
              • johnpozJ Offline
                johnpoz LAYER 8 Global Moderator
                last edited by

                Oh you meant R-6413 ;)  Yeah that is in Utah…

                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 2.8.1, 25.07.1

                1 Reply Last reply Reply Quote 0
                • J Offline
                  JonH
                  last edited by

                  @johnpoz:

                  Yeah ARIN is pretty up to date.. Not sure they would have a wrong listing for 30 address..  Are you saying you got your dhcp IP from this IP address??  I am confused on what this address has to do with anything to be honest?  Or what does it matter?  Maybe the dod uses your same ISP??  And they are running multiple layer 3 networks on the same layer 2 ;)

                  I'm confused too, that is why I posted here looking for suggestions.  My logs have wrapped around since I started this so I don't have documentation now.

                  This is a typical entry from dhcp log.  I do note the acknowledging server is from a different IP than yesterday but this IP is registered to my ISP, which is the cable company Charter Communications.  My connection is via cable modem.

                  Nov 21 04:07:42 	dhclient 	27954 	DHCPREQUEST on igb0 to 68.114.36.9 port 67
                  Nov 21 04:07:42 	dhclient 	27954 	DHCPACK from 68.114.36.9
                  Nov 21 04:07:42 	dhclient 		RENEW
                  Nov 21 04:07:42 	dhclient 		Creating resolv.conf
                  Nov 21 04:07:42 	dhclient 	27954 	bound to x.x.x.x -- renewal in 12752 seconds.
                  Nov 21 04:41:30 	dhcpd 		Wrote 0 deleted host decls to leases file.
                  Nov 21 04:41:30 	dhcpd 		Wrote 0 new dynamic host decls to leases file.
                  Nov 21 04:41:30 	dhcpd 		Wrote 16 leases to leases file. 
                  

                  What that looks like is a dhcpack.. So your saying that is what is giving you your IP??  Then either your ISP is the DOD ;)  Or what is more likely is they are using IPs that are not theirs because they don't think anyone will be talking to those IPs..  While its BAD practice, it is common practice..  Again its BAD practice.. but happens more than you think.. Companies to lazy to do proper IPAM or subnetting or natting when required..  Hey lets grab these /8's that are owned by DOD - nobody is going to be going there ;)

                  Or for the really paranoid, it's the NSC's backdoor into a large US customer base.

                  I cannot say that 30.85.128.1 is giving me my IP.  For the last month or so I've noticed everytime my lease was renewed there is a message in the log that there are 2 dhcp servers.  That is news to me.  But now that I have found this DoD server maybe that is the cause of that message.

                  I can only say that this IP is in my firewall log.  My dhcp log shows my request being ack by Charter's IP.  I first discovered this when I did a halt on pfSense so I could relocate the SG2440.  I then looked at the logs after restarting, I had never done a cold startup since putting it into service.  I found that odd IP in the firewall log about the same point in time that my DHCP request was being ACK.  I didn't recognize it and did a whois.  That started this thread.  I blocked that IP and it continued to hammer 2x every 10 minutes throughout the night.  I recently unblocked that rule.

                  Now that I've been through this discussion and looked at the logs for awhile, I'd have to repeat that cold startup and capture the logs to review.  I think it's pretty crazy.

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

                    Hey lets grab these /8's that are owned by DOD - nobody is going to be going there

                    Except aliens.  ;)

                    PfSense running on Qotom mini PC
                    i5 CPU, 4 GB memory, 32 GB SSD & 4 Intel 1 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
                    • johnpozJ Offline
                      johnpoz LAYER 8 Global Moderator
                      last edited by

                      I don't see how its crazy.. Since this is broadcast traffic and can only be on layer 2, which is your ISP.. Contact your ISP if your curious/concerned.  But going to say this yet again.  Just because the IP is registered to the DOD doesn't mean its not your ISP using it, or could just be some idiot down the street running a dhcp server on his wan and he is using dod address space..

                      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 2.8.1, 25.07.1

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

                        @johnpoz:

                        could just be some idiot down the street running a dhcp server on his wan and he is using dod address space..

                        One, two, three of them just here on the forum…

                        ;D ;D ;D

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

                          ^ heheh exactly!!!  So see if they plugged that interface into their isp device the wrong way.. Big Bang Zoom there you go a dod address space dhcp server on some ISP layer 2 network.  Where all the users on that network could see the traffic..  Hopefully they don't get an IP from it ;)  You would HOPE!!!! That the isp is running stuff to prevent unauthorized dhcp servers on the layer 2 between them and their customers.  But you never know….

                          So what I would do is email your isp support, showing them dhcp traffic and the IP and asking if that is them...  Or one of their other idiot users..

                          Whats the mac address coming from that 30 address?  We can look it up and see what kind of hardware it is, or the maker of 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 25.07.1 | Lab VMs 2.8.1, 25.07.1

                          1 Reply Last reply Reply Quote 0
                          • J Offline
                            JonH
                            last edited by

                            @johnpoz:

                            Whats the mac address coming from that 30 address?  We can look it up and see what kind of hardware it is, or the maker of it..

                            So I would need to have a packet trace running at the moment in time that the misconfigured device makes a request?  Or is there another way that I am not thinking about?

                            1 Reply Last reply Reply Quote 0
                            • K Offline
                              kpa
                              last edited by

                              ARP table, it's there exactly for the purpose of seeing the MAC addresses of network peers on the same network segment.

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

                                ^^^^
                                An arp cache has a limited lifetime, so he'd have to check it within a short period of time.  However, if he can ping that address and get a response, the arp cache would have the MAC.  Failing that, just let the packet capture run, filtering on that IP address.

                                PfSense running on Qotom mini PC
                                i5 CPU, 4 GB memory, 32 GB SSD & 4 Intel 1 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
                                • J Offline
                                  JonH
                                  last edited by

                                  The IP does not respond to a ping.  But my ISP's dhcp does respond to a ping.

                                  I think the only option is a packet capture.  Not sure I want to leave it running for an extended period of time.

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

                                    @johnpoz:

                                    ^ heheh exactly!!!

                                    +1

                                    Had a large fire agency in my county trying to hand out DHCP to cable system customers for almost two weeks till the techs paid them a visit.  ;D ::)

                                    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 0
                                    • K Offline
                                      kpa
                                      last edited by

                                      At least my ISP is sneaky enough to isolate its clients from each other:

                                      
                                      $ ifconfig em1
                                      em1: flags=8843 <up,broadcast,running,simplex,multicast>metric 0 mtu 1500
                                              options=209b <rxcsum,txcsum,vlan_mtu,vlan_hwtagging,vlan_hwcsum,wol_magic>ether 00:1b:21:14:ca:5e
                                              inet6 fe80::21b:21ff:fe14:ca5e%em1 prefixlen 64 scopeid 0x3
                                              inet 88.xxx.yyy.181 netmask 0xffffe000 broadcast 88.xxx.zzz.255
                                              inet 192.168.1.200 netmask 0xffffff00 broadcast 192.168.1.255
                                              nd6 options=21 <performnud,auto_linklocal>media: Ethernet autoselect (100baseTX <full-duplex>)
                                              status: active
                                      
                                      $ ping 88.xxx.yyy.182
                                      PING 88.xxx.yyy.182 (88.xxx.yyy.182): 56 data bytes
                                      ^C
                                      --- 88.xxx.yyy.182 ping statistics ---
                                      1 packets transmitted, 0 packets received, 100.0% packet loss
                                      
                                      $ arp -an
                                      ...
                                      ? (88.xxx.yyy.182) at 00:0b:45:b6:ef:c0 on em1 expires in 1058 seconds [ethernet]
                                      ? (88.xxx.yyy.181) at 00:1b:21:14:ca:5e on em1 permanent [ethernet]
                                      ? (88.xxx.yyy.1) at 00:0b:45:b6:ef:c0 on em1 expires in 90 seconds [ethernet]
                                      ...</full-duplex></performnud,auto_linklocal></rxcsum,txcsum,vlan_mtu,vlan_hwtagging,vlan_hwcsum,wol_magic></up,broadcast,running,simplex,multicast> 
                                      

                                      The .181 is my current IP address and the .1 address is the gateway on the WAN network and it (or more likely some equipment between me and the gateway device) seems to just proxy ARP every single IP address of the WAN network that is not assigned to you.

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

                                        ^^^^
                                        Are you on a cable modem?  I am and can see the arp requests for others, including on other subnets.  However, I can't see any traffic from the others, as cable modems have separate channels for each direction.

                                        PfSense running on Qotom mini PC
                                        i5 CPU, 4 GB memory, 32 GB SSD & 4 Intel 1 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
                                        • chpalmerC Offline
                                          chpalmer
                                          last edited by

                                          @JKnott:

                                          ^^^^
                                          Are you on a cable modem?  I am and can see the arp requests for others, including on other subnets.  However, I can't see any traffic from the others, as cable modems have separate channels for each direction.

                                          I can see every one of the cable modems via their local maintenance IP address on my system.

                                          The reason you don't see their traffic is because the system acts like a switch and not a hub. They do block network shares however.

                                          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 0
                                          • K Offline
                                            kpa
                                            last edited by

                                            I'm on (A)DSL of a type that encapsulates ethernet frames into ATM, no PPPo(E|A). This type of connection would normally allow client to client traffic because it's just standard ethernet by all means, I've seen it working on a similar ADSL connection from my previous ISP many years ago but my current one (Sonera) seems to have other ideas.

                                            Oh and of course we are only talking about layer 2 isolation here to disable broadcast based services such as DHCP, IP level connections such as SSH will still get trough.

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