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

    pfSense WAN interface wont get IP address

    Scheduled Pinned Locked Moved General pfSense Questions
    wandhcpisp
    18 Posts 6 Posters 33.9k 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.
    • stephenw10S
      stephenw10 Netgate Administrator
      last edited by

      Check the dhcp logs. As I said on the other thread you posted in, run a packet capture on WAN to make sure something is going out/coming back.

      The most likely scenario is that the modem is locked to the MAC address of the previous router. Try spoofing that MAC address on the pfSense WAN.
      Try connecting something else entirely to the modem, can that pull a dhcp lease?

      Steve

      1 Reply Last reply Reply Quote 0
      • R
        richrichgreen
        last edited by richrichgreen

        @stephenw10 said in pfSense WAN interface wont get IP address:

        packet capture on WAN

        pfSense dhcp stuff.txt 2020-04-07_4-12-35.jpg
        Here are the DHCP and a packet capture on the WAN interface, I already tried spoofing the MAC address, with no luck. And plugging the modem into my PC I get an IP address.

        1 Reply Last reply Reply Quote 0
        • stephenw10S
          stephenw10 Netgate Administrator
          last edited by

          Ok, the dhclient had some fixes in 2.4.5 and appears to be working as expected there. It sends requests and gets no replies, fails and restarts.
          The packet capture shows the same thing. The modem/ISP is just not responding at all.

          Maybe a problem with the hypervisor setup?

          Try plugging the pfSense WAN into some other dhcp server, does it pull a lease then?

          Steve

          1 Reply Last reply Reply Quote 0
          • ?
            A Former User
            last edited by

            Cold boot the Arris TM1602 Modem after switching to pfSense. Had this situation once with another Cable Provider and another modem. Worked like magic after that move.

            O 1 Reply Last reply Reply Quote 0
            • stephenw10S
              stephenw10 Netgate Administrator
              last edited by

              Yeah, it sure looks exactly like a cable modem that is locked to a different MAC.

              But if that were the case it would not have handed an IP to both the PC and the other router. Unless the cold boot was colder at that point. ๐Ÿ˜‰

              Steve

              1 Reply Last reply Reply Quote 0
              • ?
                A Former User
                last edited by

                @stephenw10 said in pfSense WAN interface wont get IP address:

                But if that were the case it would not have handed an IP to both the PC and the other router. Unless the cold boot was colder at that point.

                Ok, overlooked that part - No need to put the modem into the fridge before booting again ๐Ÿ˜‚

                1 Reply Last reply Reply Quote 0
                • stephenw10S
                  stephenw10 Netgate Administrator
                  last edited by

                  When in this sort of situation it is easy to miss something and think you're run a test that in fact did not happen.

                  It seems so like a MAC address issue that I would retest it to be sure. Power down the modem completely, connect pfSense, retest.

                  Steve

                  DaddyGoD 1 Reply Last reply Reply Quote 0
                  • DaddyGoD
                    DaddyGo @stephenw10
                    last edited by

                    @stephenw10

                    this problem has been around for a long time, for example with this type of Sagem F @ st 3890 V3 DOCSIS 3.1 (Telekom Hungary)

                    The solution: from Cisco E900 + DD-WRT router MAC address spoofing and it works for me

                    Only pfSense does not picks up the Dynamic IP, other devices doin well (PcEngine APU4 board WAN interface)

                    Cats bury it so they can't see it!
                    (You know what I mean if you have a cat)

                    1 Reply Last reply Reply Quote 0
                    • stephenw10S
                      stephenw10 Netgate Administrator
                      last edited by

                      Hmm, well if that is an issue it's one I'm not aware of. Because the MAC is not spoofed?

                      There was a bug in the dhcpclient as I said but that is fixed in 2.4.5. It would not have prevented MAC spoofing functioning though.

                      Steve

                      DaddyGoD 1 Reply Last reply Reply Quote 0
                      • DaddyGoD
                        DaddyGo @stephenw10
                        last edited by

                        @stephenw10
                        this status then it occurs, if the next device set is on the provider's side, Cisco CMTS and edgeQAM with Prerequisites for Cable DHCP Leasequery / DHCP MAC Address Exclusion List, configured in Cisco IOS for some reason this is not liked by pfSense

                        Cats bury it so they can't see it!
                        (You know what I mean if you have a cat)

                        1 Reply Last reply Reply Quote 0
                        • stephenw10S
                          stephenw10 Netgate Administrator
                          last edited by

                          If it's something you can replicate in 2.4.5 then open a bug report for it one is not open already: https://redmine.pfsense.org/

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

                            Cable systems (at least here in the US) lock to a certain number of MAC addresses. Usually one if you are a residential customer. My ISP gives out two. Commercial customers may get upwards of 25 depending on the ISP. After you exhaust your "allowance" you must reboot the modem if you want to change devices.

                            The cable modem is a bridge. It bridges an RF solution to an Ethernet solution in simple terms. (whether or not it has a built in router is both relevant and irrelevant for this point. Relevant only if the onboard router is active as it would be the "Mac" address registered with the head end.)

                            Rebooting the cable modem causes the cable systems head end to release the MAC addresses and allow new entries.

                            When you read a doc like this- https://support.usr.com/support/6000/6000-ug/two.html

                            Understand that the point when the article says-
                            "The cable modem broadcasts a DHCP request. The CMTS will forward this request to a DHCP server located on the cable operator's network. The DHCP server will, in the most basic of systems, register the cable modem by looking at its unique Ethernet MAC address (different from the MAC layer in the DOCSIS protocol model) and assign to it an IP address from a pool of IP addresses."
                            that this is not the IP address assigned to your WAN of your router. It is only the address that is assigned to the modem itself for communications from the ISP for diagnostic and control. Basically they give it an address so they can reach it. (Some modems allow the GUI to be seen on this address and by anybody on the same cable system. Older modems were really easy to reboot by other customers. But it was a mostly unknown fact so no wide spread abuse.)

                            It is only after the modem has gone through all of its boot up that data can be passed from one end to the other. (Ethernet to the cable side.) This is when the router should actually be started.

                            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
                            • DaddyGoD
                              DaddyGo
                              last edited by

                              I know CATV systems pretty well (especially over coax + DOCSIS), at least I have thought so far, specifically the DHCP process and endpoint protection in such systems
                              during a couple of few weeks we investigated the origin of the problem with Telekom sysadmin and the conclusion became that it could be an unknown compatibility issue
                              this is not necessarily just a pfSense problem as we have not come to a specific conclusion
                              there was no serious solution, I was just looking for an old Cisco E900 and cloned the wan interface MAC in pfSense
                              it seems to be certain that the issue with Cisco hardware (CMTS) and IOS setup is the thing on CATV DOCSIS network + pfSense end environment
                              this is evidenced by the fact that the MAC address is cloned from Cisco or Linksys hardware it immediately connected to CISCO CMTS + Cisco vendor MAC on endpoint
                              if we connect a non-pfSense OS based device to the modem (which is in bridge mode), we will still get an IP address with DHCP
                              since this installation is in one of our company's external site, so there are not much times possible to shut down the device to lose the MAC entry in CMTS
                              the faults that we experienced was a prolonged power failure, as there was an electrical maintenance (on the electricity network of the service provider) for 8 hours and we had to shut down the UPSs
                              this condition is very rare, but as I have the opportunity I will look into the issue on 2.4.5 as well

                              br, Krisztian

                              Cats bury it so they can't see it!
                              (You know what I mean if you have a cat)

                              1 Reply Last reply Reply Quote 1
                              • R
                                richrichgreen
                                last edited by

                                So I setup a new pfSense machine that wasn't vitalized, and it works perfectly no problems. No MAC spoofing, didn't even need to reboot the modem. So the problem is either the port on the other machine (Dell R220) or more likely my Hyper-V setup. Any suggestions on what settings I may have messed up?

                                1 Reply Last reply Reply Quote 0
                                • DaddyGoD
                                  DaddyGo
                                  last edited by

                                  As Steve wrote, this is probably no longer a problem on 2.4.5.
                                  It is necessary to test in several pfSense based systems with different NICs.
                                  I can tell you, I have never had problem with the following config: Dell R210II + onboard Broadcom (BCM5716C) and / or I350-F4 / T4 add-on

                                  Cats bury it so they can't see it!
                                  (You know what I mean if you have a cat)

                                  1 Reply Last reply Reply Quote 0
                                  • stephenw10S
                                    stephenw10 Netgate Administrator
                                    last edited by

                                    I would guess it's something in the Hyper-V setup.

                                    As I suggested before, try connecting the WAN to some other local DHCP server. Does it pull a lease from that?

                                    If not it's something at layer 2 preventing it. The NIC not passed through correctly for example. Though you might consider that layer 1 I guess. ๐Ÿ˜‰

                                    Steve

                                    1 Reply Last reply Reply Quote 0
                                    • O
                                      oscardiaz327 @A Former User
                                      last edited by

                                      Using Spectrum as ISP and was pulling my hair out on why the Netgate sg-2100 wasn't getting a WAN ip address. After unplugging the modem and the Netgate for a few minutes, then plugging in the cable modem then the Netgate did it get a WAN IP address on the device, thanks!

                                      1 Reply Last reply Reply Quote 0
                                      • jimpJ jimp moved this topic from Problems Installing or Upgrading pfSense Software on
                                      • First post
                                        Last post
                                      Copyright 2025 Rubicon Communications LLC (Netgate). All rights reserved.