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    OpenVPN compression

    Scheduled Pinned Locked Moved General pfSense Questions
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    • emammadovE
      emammadov
      last edited by emammadov

      It is not clear to me. I want to say comprehensively. We are using pfsense at our office at the moment. Adaptive LZO Compression has been choosen in VPN / OpenVPN / Servers. Jimp and pfSenseTest users said that don't use Compression at the moment and disable it because of VORACLE attack. So I changed compression from "Adaptive LZO Compression" to "Disable Compression, retain compression packet framing (compress)". But after it, when users connects, they don't see our network, I switched it back, it began to work. Now I have question that, after disabling Compression, should I export new vpn files for users?

      Elvin

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      • jimpJ
        jimp Rebel Alliance Developer Netgate
        last edited by

        The clients all have to be changed to match. Everyone has to agree on the compression setting, or you have to set the server to push it.

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        • emammadovE
          emammadov
          last edited by emammadov

          Thanks, after I selected "Push Compression" in OpenVPN, there is new entries in Systems Logs, which I have never seen before. Is it normal?

          Mar 14 21:11:46 kernel em0: promiscuous mode enabled
          Mar 14 21:11:46 kernel bge0: promiscuous mode enabled
          Mar 14 21:11:46 kernel vr0.460: promiscuous mode enabled
          Mar 14 21:11:46 kernel vr0: promiscuous mode enabled
          Mar 14 21:11:46 kernel re1: promiscuous mode enabled
          Mar 14 21:11:46 kernel re0: promiscuous mode enabled
          Mar 14 21:11:45 kernel em0: promiscuous mode disabled
          Mar 14 21:11:45 kernel bge0: promiscuous mode disabled
          Mar 14 21:11:45 kernel vr0.460: promiscuous mode disabled
          Mar 14 21:11:45 kernel vr0: promiscuous mode disabled
          Mar 14 21:11:45 kernel re1: promiscuous mode disabled
          Mar 14 21:11:45 kernel re0: promiscuous mode disabled
          Mar 14 21:11:45 kernel pid 7858 (ntopng), uid 0: exited on signal 11 (core dumped)

          Elvin

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          • stephenw10S
            stephenw10 Netgate Administrator
            last edited by

            None of those are OpenVPN related.

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            • PippinP
              Pippin
              last edited by

              Probably from packet capture?

              I gloomily came to the ironic conclusion that if you take a highly intelligent person and give them the best possible, elite education, then you will most likely wind up with an academic who is completely impervious to reality.
              Halton Arp

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              • stephenw10S
                stephenw10 Netgate Administrator
                last edited by

                Looks more like ntopng restarting, taking all the interfaces out of promiscuous mode and then putting them back in.

                Still unrelated to OpenVPN though. ๐Ÿ˜‰

                Steve

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                • emammadovE
                  emammadov
                  last edited by emammadov

                  I have still the same issue. I installed fresh pfsense and disabled compression. Windows machines and mobile phones connects and can access local network. Linux machines connects but can't access local network. I exported vpn files of Viscosity Bundle in Openvpn Client Export and imported files in Openvpn / Network Connection in Linux Mint, If I use compression in openvpn server and export new files and import them in Linux OS, then Linux machines can access local network.

                  But I export Archive in Openvpn server in pfSense and open terminal in Linux and run this command:
                  sudo openvpn --config user.ovpn and enter username and password then it connects and can access local network.

                  Elvin

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                  • stephenw10S
                    stephenw10 Netgate Administrator
                    last edited by

                    You can edit the VPN connection in Linux Mint to change the compression settings.
                    Does it match what you set in pfSense? Can you change it to match? Does that then allow access?

                    Steve

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                    • emammadovE
                      emammadov
                      last edited by

                      If I choose one of options in Compression, save and export new fles and import them in Linux Mint, then I connect and access local network.
                      Default was "Omit Preference (Use Openvpn Default). Because of Voracle attack, I choose "Disable Compression, retain compression packet framing (compress)".

                      There is also option in Compression settings: "No LZO Compression (Legacy style, comp-lzo-no)".

                      To disable Compression, did I choose the right option? - "Disable Compression, retain compression packet framing (compress)".

                      Elvin

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                      • emammadovE
                        emammadov
                        last edited by emammadov

                        "Disable Compression, retain compression packet framing (compress)" is selected in Compression. And I checked "Push Compression", after that, when I connect vpn, I can access local network. But I wonder why I have to check Push Compression?

                        But I ask again. To disable Compression, did I choose the right option? - "Disable Compression, retain compression packet framing (compress)".

                        Elvin

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                        • stephenw10S
                          stephenw10 Netgate Administrator
                          last edited by

                          What does it show in the client in Mint when you do that?

                          I always choose omit preference there unless the other end has some specific setting that requires it.

                          Steve

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                          • emammadovE
                            emammadov @stephenw10
                            last edited by

                            @stephenw10 It shows nothing. I suggest you do it in your test environment to make sure why it happens, maybe there is a bug and it needs to be fixed. I read again that pfsense developers says don't use compression and disable it, because you may be a victim of Voracle attack.

                            Elvin

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                            • stephenw10S
                              stephenw10 Netgate Administrator
                              last edited by stephenw10

                              I have such a tunnel configured right now. It works fine with the inline config imported to Mint, I can ping across it.

                              Selection_596.png

                              That's against an SG-1100 running 2.4.4p2

                              In Mint that looks like this:
                              Selection_597.png

                              Steve

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                              • emammadovE
                                emammadov
                                last edited by

                                Select Disable Compression in Compression settings and uncheck Push Compression in Openvpn server, then export bundle and import in Linux Mint. You will see what I mean.

                                Elvin

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                                • stephenw10S
                                  stephenw10 Netgate Administrator
                                  last edited by

                                  Compression is disabled by default, why would I do that?

                                  You still haven't said what Mint shows it's using for compression in the situation where there is seemingly a mismatch.

                                  Steve

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                                  • GertjanG
                                    Gertjan
                                    last edited by

                                    Just checking :

                                    a3360caa-533a-4a1b-b926-89f3f89b7df5-image.png

                                    really ? tap !?

                                    No "help me" PM's please. Use the forum, the community will thank you.
                                    Edit : and where are the logs ??

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                                    • stephenw10S
                                      stephenw10 Netgate Administrator
                                      last edited by

                                      Ha, yeah I was testing everything on the 1100. That just happened to be the last thing I tested there. ๐Ÿ˜‰

                                      Steve

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                                      • emammadovE
                                        emammadov
                                        last edited by emammadov

                                        in your screenshot Omit Preference has been chosen in Compression in Openvpn Server. In my side, I have chosen "Disable Compression, retain compression packet framing (compress)" in Compression in Openvpn Server. I want to disable compression on server side and when I export vpn files of client, it will be automatically disabled on client side as well. But if I don't check Push Compression, then Linux users can't access local network when they are connected. I want to know why it happens?

                                        There is no need to check Push Compression when Omit Preference is checked in Compression?

                                        My screenshot is as follows.

                                        Screenshot from 2019-03-25 21-18-54.png

                                        Elvin

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                                        • stephenw10S
                                          stephenw10 Netgate Administrator
                                          last edited by

                                          I would only expect to have to push the compression setting if you have changed it to something other than the default.

                                          Steve

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                                          • emammadovE
                                            emammadov
                                            last edited by emammadov

                                            It doesn't matter which compression setting I choose and keep Push compression unchecked, it is working well both in Windows and Linux machines. But if I choose Disable compression in Openvpn server and keep Push compression unchecked, then it is not working in Linux machines. To make it working, I have to check Push compression.

                                            I have this logs in Openvpn Logs when Disable Compression and Push compression is checked. If I uncheck Push Compression, everything is okay in logs.

                                            Mar 26 16:06:31 openvpn 29296 XX.XX.XX.XXX:60636 peer info: IV_TCPNL=1
                                            Mar 26 16:06:31 openvpn 29296 XX.XX.XX.XXX:60636 WARNING: 'link-mtu' is used inconsistently, local='link-mtu 1550', remote='link-mtu 1549'
                                            Mar 26 16:06:31 openvpn 29296 XX.XX.XX.XXX:60636 WARNING: 'comp-lzo' is present in local config but missing in remote config, local='comp-lzo'
                                            Mar 26 16:06:31 openvpn 29296 XX.XX.XX.XXX:60636 [elvin] Peer Connection Initiated with [AF_INET]XX.XX.XX.XXX:60636
                                            Mar 26 16:06:31 openvpn user 'elvin' authenticated

                                            Elvin

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