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    pfSense mangling packets?

    Scheduled Pinned Locked Moved General pfSense Questions
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    • johnpozJ
      johnpoz LAYER 8 Global Moderator @Tueem
      last edited by

      @Tueem I sure can - that was from a client behind pfsense.

      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 24.11 | Lab VMs 2.8, 24.11

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        Tueem @johnpoz
        last edited by Tueem

        @johnpoz Yeah but for me it isn't and I'm trying to figure out why and how to fix that.
        Any Client behind my pfsense errors out which can be seen in the images I sent.

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

          @Tueem your packet capture you see them send a fin.. There is your syn, then their syn,ack and and they send a fin.. Now sure how you think that points to "managled" packets. Maybe they just don't like your IP? You say it works outside pfsense - but is that IP you talk to them from the same?

          fin.jpg

          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 24.11 | Lab VMs 2.8, 24.11

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            Tueem @johnpoz
            last edited by

            @johnpoz Yeah the WAN is just my ISPs Router. When I connect directly to the ISP router I can access the site no problem and even doing the curl in pfsense itself works fine.

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            • johnpozJ
              johnpoz LAYER 8 Global Moderator @Tueem
              last edited by

              @Tueem maybe they are looking for a specific source port in your traffic? Pfsense will change the source port when it nats, some soho/isp routers do not do this.. If your double natting and you see this when only when pfsense is behind your isp nat router.. you would get this.

              client ip:X --> server IP:Y pfsense wan IP:A --> server IP:Y isp router public IP:A --> server IP:Y

              Set pfsense outbound nat for a client to static nat..

              staticport.jpg

              You would then end up with this

              client ip:X --> server IP:Y pfsense wan IP:X --> server IP:Y isp router public IP:X --> server IP:Y

              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 24.11 | Lab VMs 2.8, 24.11

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              • stephenw10S
                stephenw10 Netgate Administrator
                last edited by

                I note in your pcap there don't seem to be any significantly sized packets. You could have an MTU issue.

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                  Tueem @johnpoz
                  last edited by

                  @johnpoz That did not fix it unfortunately.

                  johnpozJ 1 Reply Last reply Reply Quote 0
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                    Tueem @stephenw10
                    last edited by

                    @stephenw10 Can you elaborate? I've changed to MTU settings and left all the boxes empty.

                    stephenw10S 1 Reply Last reply Reply Quote 0
                    • johnpozJ
                      johnpoz LAYER 8 Global Moderator @Tueem
                      last edited by

                      @Tueem well pfsense doesn't "mangle" traffic.. And if it was then you would be having way more issues than just this one thing that runs something other than actual https over the standard 443 port.

                      Not sure what you were doing when you sniffed that - was that during your curl test? But the server sent you a fin, so he told you he was done..

                      I don't play minecraft, but I guess I could try fire it up.. Do I need to create an account at some specific site so it will talk to this 13.x address? That 13.x address is owned by MS.. Prob some service hosted in azure..

                      What is the exact error you get when you try and play minecraft? I know my grandkids have played it on their phones while they have been here over my wifi, and they had no issues.

                      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 24.11 | Lab VMs 2.8, 24.11

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                      • stephenw10S
                        stephenw10 Netgate Administrator @Tueem
                        last edited by

                        @Tueem said in pfSense mangling packets?:

                        Can you elaborate?

                        Well it's hard to see from a picture of the pcap text but it looks like it's only seeing small packets. In an established TCP connection I'd expect to see large packets at the path MTU size. So at least 1400 for most connections.

                        If you do not see that in the full pcap then you might have an MTU issue somewhere.

                        johnpozJ 1 Reply Last reply Reply Quote 0
                        • johnpozJ
                          johnpoz LAYER 8 Global Moderator @stephenw10
                          last edited by

                          @stephenw10 while I agree when your moving data your packets should get bigger.. But that 13.x box sends a fin right way, all we are seeing there is the handshake.

                          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 24.11 | Lab VMs 2.8, 24.11

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                            Tueem @johnpoz
                            last edited by

                            @johnpoz Yeah the tcpdump output was during the curl.
                            After further investigation I figured out that that 13.x address is the one that minecraft.net resolves to.
                            I host a paper-1.8 server that runs through a Wireguard VPN and when I try to connect it just tells me that the authentication servers are down. I got the IP by sniffing the firewall logs and looking for IPs my server tried to connect to.
                            On my PC which doesn't go through the VPN it connects fine. (I can confirm its not an issue of the VPN because if I use the official wireguard client directly it connects just fine.)

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

                              @Tueem said in pfSense mangling packets?:

                              I can confirm its not an issue of the VPN because if I use the official wireguard client directly it connects just fine.

                              Like from the server directly?

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                                Tueem @stephenw10
                                last edited by

                                @stephenw10 From my PC directly yes

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                                • stephenw10S
                                  stephenw10 Netgate Administrator
                                  last edited by

                                  Hmm, same server I assume?

                                  Where did you run the pcap from above?

                                  Does it show a similar failure when actually looking for the traffic to the minecraft auth server?

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                                    Tueem @stephenw10
                                    last edited by

                                    @stephenw10 Yes the same Wireguard endpoint and same IP all the same.

                                    The test above is from tcpdump on the pfsense box using the lan nic.

                                    I've attached the tcpdump on the same interface which happens when i try to connect to the server (not curling)

                                    NOTE: The IP of minecraft.net has changed but the behaviour stays the same

                                    32761874-751b-4161-b536-bc8f2fb9c9d9-image.png

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                                    • johnpozJ
                                      johnpoz LAYER 8 Global Moderator @Tueem
                                      last edited by johnpoz

                                      @Tueem here he is sending you a reset.. Which is not hey I am done with this conversation (fin).. He is saying GO AWAY I am done talking to you, I don't care if you still want to continue the conversation or not.

                                      reset.jpg

                                      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 24.11 | Lab VMs 2.8, 24.11

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                                        Tueem @Tueem
                                        last edited by

                                        @Tueem I've attached the traffic of a successfull authentication. I acquired this by routing the server through my usual wan temporarily.

                                        cb0b1ee1-904d-4acf-85ac-39dc4fd5e5b2-image.png

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                                        • stephenw10S
                                          stephenw10 Netgate Administrator
                                          last edited by

                                          Try capturing on the WG interface and make sure it's all passing that way.

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                                            Tueem @stephenw10
                                            last edited by

                                            @stephenw10 Here is the traffic through the wg0 interface:
                                            Screenshot 2024-05-10 131442.png

                                            johnpozJ 1 Reply Last reply Reply Quote 0
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