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    Gateway offline, Packetloss

    Scheduled Pinned Locked Moved General pfSense Questions
    90 Posts 6 Posters 24.8k Views
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    • A
      Apaar @Apaar
      last edited by

      What can i do to replace the mac address for the gateway ?

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      • stephenw10S
        stephenw10 Netgate Administrator
        last edited by

        The MAC for the gateway should appear in the ARP table immediately unless the gateway doesn't reply to the ARP query. It did reply though in the pcap you uploaded. Both times pfSense queried it. You shouldn't need to do anything there.

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        • A
          Apaar @stephenw10
          last edited by

          @stephenw10 The ARP table detected the hostname for a sec of the ISP, but then it disappeared again.

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          • stephenw10S
            stephenw10 Netgate Administrator
            last edited by

            The hostname doesn't matter, only the MAC and IP address are important.

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            • A
              Apaar @stephenw10
              last edited by

              Okay but then how will this issue solve ?

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              • stephenw10S
                stephenw10 Netgate Administrator
                last edited by

                It won't. You need to make sure pfSense is actually sending the ARP query when you remove the entry fro the table. That's why you are running the pcap and filtering for ARP and the gateway IP.

                If your previous pcap the gateway starts to respond each time pfSense sends that query.

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                • stephenw10S
                  stephenw10 Netgate Administrator
                  last edited by

                  If it does then one thing we could do it set the ARP timeout much shorter. That would be a workaround though, it shouldn't be required.

                  sysctl net.link.ether.inet.max_age=300
                  

                  Steve

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                  • A
                    Apaar @stephenw10
                    last edited by

                    @stephenw10 Can you help me a bit sir, I don't know much about it. I deleted the gateway entry from the ARP table, what to do now ?

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                    • A
                      Apaar @Apaar
                      last edited by

                      After deleting the ARP table the gateway shows as incomplete mac address.

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                      • stephenw10S
                        stephenw10 Netgate Administrator
                        last edited by

                        Run a pcap and see what's happening. If it shows as incomplete in the ARP table that means pfSense is ARPing and the gateway isn't replying, which is not what was happening in the last pcap.

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                        • A
                          Apaar @stephenw10
                          last edited by

                          @stephenw10 i ll run a packet capture and send you the file in some time.

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                          • L
                            louis2 @stephenw10
                            last edited by louis2

                            @stephenw10

                            stephen if you look into ^my IPV6 thread (link send)^, you can see that:

                            • at certain moment ^pfsense^ detect that the GW is gone
                            • the GUI keeps that state ^for ever^
                            • and later on a ping shows that the GW is back again
                            • something not detected by ^pfSense^

                            So in ^my error case^ it is clear that ^pfSense^ is not behaving correctly

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                            • stephenw10S
                              stephenw10 Netgate Administrator
                              last edited by

                              @louis2 said in Gateway offline, Packetloss:

                              https://forum.netgate.com/topic/173356/issues-with-ipv6

                              You are clearly seeing some issue there but it's with DHCPv6 over PPPoE in 2.7. None of those things are in play here so it seems unrelated to me.

                              Steve

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                              • A
                                Apaar @stephenw10
                                last edited by

                                @stephenw10 Sent the Pcap on the same old link

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                                • stephenw10S
                                  stephenw10 Netgate Administrator
                                  last edited by

                                  Ok, so if you look at the pcap you can see pfSense first sends an ARP query in packet 2278 and the gateway responds correctly. Then it immediately starts responding to the other traffic.
                                  That is 776s into the pcap. Is that when you deleted the ARP entry?

                                  Traffic continues until packet 2341 at 788s. So only 12s.

                                  But later in the pcap we see traffic for 21s and then 13s so it's not consistent.

                                  However it is exactly the same behaviour we saw in the previous pcap. I also note it is still monitoring the gateway IP directly and not something external.

                                  I would retest with a client directly on the connection there and see if that still works. From what we are seeing here I wouldn't expect anything using that to work for more than 20s at a time unless it's spamming ARP queries.

                                  You could try, as a test only, setting that max_age tunable to something very low like 10s. I'm betting the connection would remain up in that situation.

                                  This really looks like someone else is also trying to use the IP address.

                                  Steve

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                                  • A
                                    Apaar @stephenw10
                                    last edited by

                                    @stephenw10 Can you please help me setting up the max age.

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                                    • stephenw10S
                                      stephenw10 Netgate Administrator
                                      last edited by stephenw10

                                      At the command line run: sysctl net.link.ether.inet.max_age=10

                                      That can really only be as a test though. 10s is a ridiculously short ARP timeout.

                                      Steve

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                                      • A
                                        Apaar @stephenw10
                                        last edited by

                                        @stephenw10 Okay Sir I will try that

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                                        • A
                                          Apaar @Apaar
                                          last edited by

                                          @stephenw10 Done Sir! Screenshot 2022-09-11 at 6.49.15 PM.png

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                                          • stephenw10S
                                            stephenw10 Netgate Administrator
                                            last edited by

                                            Did it make any difference?

                                            A 3 Replies Last reply Reply Quote 0
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