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    Problem with TCP and GRE tunnel

    Scheduled Pinned Locked Moved General pfSense Questions
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    • stephenw10S
      stephenw10 Netgate Administrator
      last edited by

      Yes please.

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        StomperG @stephenw10
        last edited by

        @stephenw10 Done

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        • stephenw10S
          stephenw10 Netgate Administrator
          last edited by

          Ok well the delay is a lot longer there but you can see the local host sends the http request almost immediately after the handshake. So packets are being lost somewhere.

          Try running pcaps on both ends of the GRE tunnel at the same time. Run the curl command and see how they compare.

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            StomperG @stephenw10
            last edited by

            @stephenw10 Just upload them. Also how can I open the pcap files to compare them?

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            • stephenw10S
              stephenw10 Netgate Administrator
              last edited by

              Using Wireshark is easiest. Though you can also just set the view to high or full in the pfSense webgui and see the timing info etc.

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                StomperG @stephenw10
                last edited by

                @stephenw10 But are you able to see any difference between them now?

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                • stephenw10S
                  stephenw10 Netgate Administrator
                  last edited by

                  Yes, you can see the local end sees the initial http request at 0.02 but no reply. It retransmits that request 10 times until it finally sees a reply at 114s.

                  At the remote end it never sees any requests arrive until 114s.

                  Something is dropping those packets in the route. They are not large packets so not an MTU issue that might be caused by encapsulation.

                  I assume you gateways setup for the GRE tunnel, do you see packet loss logged on them?

                  Just to confirm; are you using encryption here? GRE over IPSe transport?

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                    StomperG @stephenw10
                    last edited by

                    @stephenw10 On both sides pf say 0.0% packet loss while using curl. Also no, im not using encryption or GRE over IPSe

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                    • stephenw10S
                      stephenw10 Netgate Administrator
                      last edited by

                      Hmm. What happens if you run curl against the webgui at the remote side?

                      Or try running an iperf test between the two pf instances.

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                      • stephenw10S
                        stephenw10 Netgate Administrator
                        last edited by

                        Also try running a pcap on the WAN interface of the local pf when running that same curl test. You should not see any traffic leaving there directly other than the GRE encapsulated traffic.

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                          StomperG @stephenw10
                          last edited by

                          @stephenw10 I already tried to see the traffic on WAN (local pf) and theres no traffic. I will try the other 2 things give me a sec

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                          • stephenw10S
                            stephenw10 Netgate Administrator
                            last edited by

                            The other thing to test would be a pcap on both WANs at the same time so you can check if GRE packets are leaving the local WAN and just not arriving at the remote WAN. I.E. is it an actual problem in the route somewhere.

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                              StomperG @stephenw10
                              last edited by

                              @stephenw10 I can curl without problems on the remote one. Also how can i do a iperf?

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                                StomperG @stephenw10
                                last edited by StomperG

                                @stephenw10 I did it now and theres no logs on the local side (WAN) while doing a pcap

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                                • stephenw10S
                                  stephenw10 Netgate Administrator
                                  last edited by

                                  iperf is a package you can install in the gui. You can also install just the backend pkg at the command line if you want.

                                  @StomperG said in Problem with TCP and GRE tunnel:

                                  I did it now and theres no logs on the local side (WAN) while doing a pcap

                                  So the local side isn't actually sending GRE packets even though the pcap on the GRE interface shows them?

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                                    StomperG @stephenw10
                                    last edited by

                                    @stephenw10 At least the WAN pcap on the local dont show anything

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                                    • stephenw10S
                                      stephenw10 Netgate Administrator
                                      last edited by

                                      Nothing at all? It must show the GRE packets if the curl command succeeds. Or do you mean just during the unexpected delay?

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                                        Konstanti @StomperG
                                        last edited by Konstanti

                                        @StomperG

                                        Hi
                                        maybe this will help
                                        I don't remember why I set up the rules this way (I think I read it in some article), but
                                        1 GRE interface (MSS 1380)
                                        2 created this floating rule for GRE interface (TUN100)

                                        2905ff65-7d7b-44ad-886b-194a33695453-image.png

                                        5f98e495-11ba-4640-9423-b5f92765c0ba-image.png

                                        7bdb0851-9887-4081-8261-86ebdd87988a-image.png

                                        here is an example of the information transfer rate through a tunnel with these settings

                                        d5ea36cd-2932-4b0b-841b-aca9563b9b03-image.png

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                                        • stephenw10S
                                          stephenw10 Netgate Administrator
                                          last edited by stephenw10

                                          That can be required for GRE+IPSec transport. Although there is now an option to allow it without that: https://redmine.pfsense.org/issues/12289

                                          However in that situation the initial handshake would fail. And that shouldn't apply here because it's not encrypted. But....anything's possible!

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                                            StomperG @stephenw10
                                            last edited by StomperG

                                            @stephenw10 Hey that's for the local or remote pf? I tried on local and had the same result :/

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