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    resolved - FTP : connection closed by remote host

    Scheduled Pinned Locked Moved Routing and Multi WAN
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    • johnpozJ
      johnpoz LAYER 8 Global Moderator
      last edited by johnpoz

      And are you using active or passive?

      In active the server will try and connect back to the client.. With passive the server will send an IP and port that the client connects to..

      So you would need to make sure the ftp server sends the correct IP to the client that it can get to, and you would need to make sure the ports that server would use for the passive range are forwarded as well.

      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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      • L
        LLFT
        last edited by

        I use the passive mode.
        I noticed in my screenshots the frame "Request: PORT 10,8,9,11,236,54" and thus allowed my FTP 2 to communicate with the VPN tunnel.

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        • johnpozJ
          johnpoz LAYER 8 Global Moderator
          last edited by johnpoz

          Your not using passive your seeing a port command...

          That is the command issued by the client to connect to him on port 236x256 + 54 or port 59762

          Here is good write up on the differences
          https://slacksite.com/other/ftp.html

          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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          • L
            LLFT
            last edited by

            Indeed bad line "Response: 227 Entering Passive Mode (10,240,69,89,230,162)"

            FTP client 1 requests PASSIVE mode

            Below is a frame capture:
            Left: the entry of the ASA
            Right: the exit of the ASA
            Annotation 2019-10-03 162112.png

            We see that the request port does not cross the firewall

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            • L
              LLFT
              last edited by

              I still have not found the origin of my problem.

              Do you have an idea ?

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              • johnpozJ
                johnpoz LAYER 8 Global Moderator
                last edited by johnpoz

                Your problem is when your client tries to go to 10.240.69.89 port 230x256 + 162 = 59042 is not open...

                Your sniff is showing port command..

                Your not going to get ftp to work be it active or passive unless you actually understand how it works.. And then open the appropriate ports to allow the method your going to use to work...

                You would be much better off just using sftp, which would be 1 single port and you wouldn't have to worry about the data channel making another connection.

                What client are you using - how is your server setup.. for example windows ftp.exe doesn't even support passive.. And maybe your server is not setup to allow it, etc.

                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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                • L
                  LLFT
                  last edited by LLFT

                  Unfortunately, I do not master the outs.
                  I am in an industrial environment, the server and the client are black boxes.

                  I have to my knowledge only the aforementioned elements namely that the customer is in passive mode

                  I am trying to simulate FTP interaction with Windows FTP and FileZilla.

                  I'm going to look at why ports "59042 & co" would be blocked.

                  Thank you for your analysis

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                  • johnpozJ
                    johnpoz LAYER 8 Global Moderator
                    last edited by

                    if your doing active ftp, which is the only thing windows ftp.exe client supports.. Then the server will talk back to you on the port and IP given by the client.

                    Does the ftp server even know how to get back to you..

                    In your drawing the ASA would need a route to get back to pfsense for the tunnel network. Is pfsense its default route for the asa? I also noticed you list pfsense address as .255 in you drawing.. That would be wrong a /24 - since that is the broadcast address of a /24

                    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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                    • L
                      LLFT
                      last edited by

                      Je confirme l'ASA est bien la route par défaut du serveur FTP, les routes sont établies de l'ASA au VPN en passant par pfSense.

                      Le traceroute du SRV au CLT fait bien les 4 sauts prévus.

                      Il s'agit en effet d'une erreur de dessin.

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                      • L
                        LLFT
                        last edited by

                        It seems that it works, I heard your review on the windows FTP client that does not handle the passive mode.

                        So I retested with FileZilla forcing the passive mode and it works.

                        I certainly had a rule that jammed before that.

                        Thank you for your help.

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