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  • Why no STARTTLS?

    Huge fan of Beyond Compare.

    My ISP recently expressed surprise that Beyond Compare does not support "STARTTLS (Implicit TLS)". I think it probably does, but just doesn't call it that in the UI. Is there a reason this wording is not used? It caused confusion when talking to my ISP (who is more used to FileZilla).



  • #2
    BC4 Pro's FTPS Profile support does support Explicit and Implicit FTPS connections, but only supports Implicit on port 990, and uses Explicit for any other port configurations.

    It's on our wishlist to expand our port options, but in the meantime, your ISP would have to allow using port 990 for Implicit connections, which should work without issue. Our trial is fully featured and available for any testing they might need, and you or they can contact us if there are any issues we can troubleshoot.
    Aaron P Scooter Software


    • #3
      Response from my ISP...

      "Implicit FTPS is port 21 using the STARTTLS command. We don't support Explicit port 990. It is an old standard and can introduce more trouble than it's worth"


      • #4
        Your ISP is mixing up terminology.

        Implicit FTPS: Connect to port 990 and immediately start a TLS negotiation before sending any commands. This is the older standard.
        Explicit FTPS: Connect to port 21 and send an AUTH TLS (not STARTTLS) command to start TLS negotiation.

        STARTTLS is a command used for SMTP and IMAP email servers and has nothing to do with FTP.

        In Beyond Compare's "Browse" dialog for an FTP profile, you should use Protocol: FTPS (Explicit SSL). That will connect to port 21 by default and use AUTH TLS, which sounds like what they want. BC does use Implicit TLS instead if you tell it to connect to port 990 specifically, but that's the only case where we use it; for any other port we use Explicit TLS.

        In terms of FileZilla Client:

        BC's "FTPS (Explicit SSL)" is equivalent to FileZilla's "Require explicit FTP over TLS"
        Zoë P Scooter Software


        • #5

          And just to confirm: you are using Pro edition, correct?

          BC4 Std only supports FTP connections, while BC4 Pro adds FTPS (Implicit and Explicit) and SFTP connections. The Profile dialog, FTP Profile, in Pro mode will have a dropdown for switching between the protocols.

          If you are registered for Std, you can revert to trial mode to test the feature following this guide:

          And if that works, you can upgrade for the price difference using our Upgrades form:

          Aaron P Scooter Software


          • #6
            Yes, I'm using Pro version.

            My ISP has replied:

            "Haha yes you are correct, I mixed the terms up. I meant Explicit and yes it is AUTH TLS not STARTTLS. Too much time working on mail systems lately! It is good to see BC supports it and you have a great looking product.

            The strange problem we are having is that when Richard or I send a large file (say 10mb), the file cuts off part way through the upload. This only seems to happen over TLS. The server is the latest puretftd on Ubuntu 20.04.3 and we don't see the same behaviour on FileZilla. We are now enforcing TLS so it haa become an issue for Richard as he is using BC. Can you recommend a way to debug what is happening?"


            • #7
              And this reproduces as soon as he tries to transfer a single file that is large enough to trigger the issue? If so, can he enable the debug logging (Tools menu -> Options, Tweaks tab, scroll down to Log Panel). You can email into [email protected] with the log.txt and a link back to this forum thread for our reference.

              If you have a test account we can connect with you can include that, too. That's often the quickest way to troubleshoot issues like this.
              Aaron P Scooter Software