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  1. Cloudron Forum
  2. VPN
  3. Change protocol from TCP to UDP

Change protocol from TCP to UDP

Scheduled Pinned Locked Moved Solved VPN
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    • P Offline
      P Offline
      p44
      translator
      wrote on last edited by
      #1

      Dear all,

      default protocol port of OpenVPN 7494/TCP.

      Is possible to change protocol to UDP? This because some providers detect VPN over TCP and blocks that.

      Inside "app" location I saw a check on "VPN TCP Port": what if I deselect?

      Schermata 2021-03-26 alle 09.01.28.png

      Thank's a lot!

      nebulonN 1 Reply Last reply
      0
      • P p44

        Dear all,

        default protocol port of OpenVPN 7494/TCP.

        Is possible to change protocol to UDP? This because some providers detect VPN over TCP and blocks that.

        Inside "app" location I saw a check on "VPN TCP Port": what if I deselect?

        Schermata 2021-03-26 alle 09.01.28.png

        Thank's a lot!

        nebulonN Offline
        nebulonN Offline
        nebulon
        Staff
        wrote on last edited by nebulon
        #2

        @p44 not sure if possible but I guess we can also add UDP alongside TCP, have to see.

        If you uncheck the TCP port, then it simply would not be opened up in the firewall and will not be setup to be forwarded to the app. I guess in this case it kinda renders the OpenVPN app instance useless then

        P 1 Reply Last reply
        1
        • mehdiM Offline
          mehdiM Offline
          mehdi
          App Dev
          wrote on last edited by
          #3

          I am quite surprised that some providers detect and block VPN over TCP, as it should literally be impossible to distinguish between it and any other TLS-encrypted stream.

          However, it would be very valuable to add the option of using UDP instead, as it can be unstable to have TCP streams inside a TCP VPN when the network is not very reliable (the effect is called "TCP Meltdown", which is quite a badass name in my opinion ^^ https://openvpn.net/faq/what-is-tcp-meltdown/ )

          P 1 Reply Last reply
          1
          • nebulonN nebulon

            @p44 not sure if possible but I guess we can also add UDP alongside TCP, have to see.

            If you uncheck the TCP port, then it simply would not be opened up in the firewall and will not be setup to be forwarded to the app. I guess in this case it kinda renders the OpenVPN app instance useless then

            P Offline
            P Offline
            p44
            translator
            wrote on last edited by
            #4

            @nebulon Thank's a lot! Hope that feature can be added to OpenVPN so app can be used also to keep working VPN in some cases where Isp analyse Internet traffic.

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            • mehdiM mehdi

              I am quite surprised that some providers detect and block VPN over TCP, as it should literally be impossible to distinguish between it and any other TLS-encrypted stream.

              However, it would be very valuable to add the option of using UDP instead, as it can be unstable to have TCP streams inside a TCP VPN when the network is not very reliable (the effect is called "TCP Meltdown", which is quite a badass name in my opinion ^^ https://openvpn.net/faq/what-is-tcp-meltdown/ )

              P Offline
              P Offline
              p44
              translator
              wrote on last edited by
              #5

              @mehdi Several countries and individual ISPs are known to use Deep Packet Inspection (DPI) to analyse Internet traffic. In that case, OpenVPN connection is instable or useless.

              Some VPN providers suggest to switch over UDP and in some cases add the "scramble" feature, so ports can be changed during data transfer.

              Eg. see this: StrongVPN and this

              mehdiM 1 Reply Last reply
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              • P p44

                @mehdi Several countries and individual ISPs are known to use Deep Packet Inspection (DPI) to analyse Internet traffic. In that case, OpenVPN connection is instable or useless.

                Some VPN providers suggest to switch over UDP and in some cases add the "scramble" feature, so ports can be changed during data transfer.

                Eg. see this: StrongVPN and this

                mehdiM Offline
                mehdiM Offline
                mehdi
                App Dev
                wrote on last edited by
                #6

                @p44 The doc in question actually says the opposite :

                You can try UDP for a possibly faster connection, but if it can not connect, switch it to TCP.

                Which makes sense : UDP OpenVPN traffic is very specific, so easy to detect. TCP OpenVPN traffic is very hard to detect.

                P 1 Reply Last reply
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                • mehdiM mehdi

                  @p44 The doc in question actually says the opposite :

                  You can try UDP for a possibly faster connection, but if it can not connect, switch it to TCP.

                  Which makes sense : UDP OpenVPN traffic is very specific, so easy to detect. TCP OpenVPN traffic is very hard to detect.

                  P Offline
                  P Offline
                  p44
                  translator
                  wrote on last edited by
                  #7

                  @mehdi Thank's a lot! 🙂

                  1 Reply Last reply
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                  • J Offline
                    J Offline
                    johannesjom
                    wrote on last edited by
                    #8

                    Have I overlooked something, or is the OpenVPN app still only capable of TCP?

                    girishG 1 Reply Last reply
                    1
                    • J johannesjom

                      Have I overlooked something, or is the OpenVPN app still only capable of TCP?

                      girishG Offline
                      girishG Offline
                      girish
                      Staff
                      wrote on last edited by
                      #9

                      @johannesjom thanks for the reminder. This got lost in the sands of time. I pushed a new package now which supports UDP. Just enable it in the location section of the app after update. Note that client configuration files have to be redownloaded for UDP mode.

                      1 Reply Last reply
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                      • J Offline
                        J Offline
                        johannesjom
                        wrote on last edited by
                        #10

                        @girish Looks good, thanks!

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