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SFTP Connection could not be opened... (40 posts)

  • Started 8 years ago by mflight
  • Latest reply 1 year ago from Steven
  • Steven Member

    Jim, I arranged for FileCOPA support to try logging into the server via Fetch. FileCOPA said:

    "We successfully connected to you from our Mac using Fetch. We uploaded the FileCOPA installer to prove we were there.

    We still think the problem is with FileCOPA not permitting your IP address to connect. Try going to FileCOPA's security page and emptying the Denied IP Addresses list.

    The other issue may be Fetch thinks the certificate has changed. You will need to check with Fetch support on what they do if the certificate doesn't match the previous one."

    I haven't yet tried emptying the "Denied IP Addresses list", for two reasons.

    1. I disconnected from my home wireless network, and reconnected via a hotspot created by my iPhone, ie. creating a different IP. I then tried connecting to the server via Fetch. Same problem, can't connect. Therefore that seems to eliminate the problem being related to the IP address. Besides, if it was IP related, Cyberduck wouldn't work either.

    2. The blacklisted IPs within FileCOPA are probably there for good reason, hence preference is to leave them in place.

    Which brings me to the question ex FileCOPA, which I'm hoping you'll know the answer to, ie. "The other issue may be Fetch thinks the certificate has changed. You will need to check with Fetch support on what they do if the certificate doesn't match the previous one."

    Posted 1 year ago #

  • Steven Member

    Jim, I arranged for FileCOPA support to try logging into the server via Fetch. FileCOPA said:

    "We successfully connected to you from our Mac using Fetch. We uploaded the FileCOPA installer to prove we were there.

    We still think the problem is with FileCOPA not permitting your IP address to connect. Try going to FileCOPA's security page and emptying the Denied IP Addresses list.

    The other issue may be Fetch thinks the certificate has changed. You will need to check with Fetch support on what they do if the certificate doesn't match the previous one."

    I haven't yet tried emptying the "Denied IP Addresses list", for two reasons.

    1. I disconnected from my home wireless network, and reconnected via a hotspot created by my iPhone, ie. creating a different IP. I then tried connecting to the server via Fetch. Same problem, can't connect. Therefore that seems to eliminate the problem being related to the IP address. Besides, if it was IP related, Cyberduck wouldn't work either.

    2. The blacklisted IPs within FileCOPA are probably there for good reason, hence preference is to leave them in place.

    Which brings me to the question ex FileCOPA, which I'm hoping you'll know the answer to, ie. "The other issue may be Fetch thinks the certificate has changed. You will need to check with Fetch support on what they do if the certificate doesn't match the previous one."

    Posted 1 year ago #

  • Jim Matthews Administrator

    Hi Steven,

    Do you know if FileCOPA's support people were using a Mac running OS X 10.11? Apparently the version of OpenSSH on 10.11 is different from the one in 10.10, and that's one possible source of incompatibility.

    I agree, it doesn't sound like a blacklisted IP address.

    If the server key changes Fetch should put up a message to that effect, and you'd get a message from the command line ssh and sftp commands. So I don't think that's the problem.

    For whatever it's worth, I found this description of an issue with FileCOPA 9.01 and a different SFTP client:

    https://www.flashfxp.com/forum/tracker.php?do=view&tracker_bugid=1074

    I have no idea whether the problem you are seeing is related.

    Thanks,

    Jim Matthews
    Fetch Softworks

    Posted 1 year ago #

  • Steven Member

    FileCOPA support acknowledge not an IP issue, including the fact that Cyberduck connects.

    They said "Our Mac runs OSX 10.10.5", but didn't offer to update to 10.11 to test, and I've not pressed that further.

    On the point about https://www.flashfxp.com/forum/tracker.php?do=view&tracker_bugid=1074, FileCOPA says "That issue is fixed. Assuming you are running the latest release then you have that fix. Latest release is dated 4th January 2016." I assume I have latest release installed because when I click "Check for updates now" I get "No updates found".

    I'm left with thinking that it must have something to do with the key exchange, which I'm not sure what that means exactly. That's what FileCOPA logs are saying, ie. "SFTP: Error - Key exchange failed." Is that something that I can re-set, Jim? Is it possible that uninstalling Fetch then reinstalling would make a difference ?

    Posted 1 year ago #

  • Jim Matthews Administrator

    No, reinstalling Fetch won't help. The problem is between FileCOPA and the OpenSSH software in 10.11 (that's why you can't connect using the command line tools either; they also use OpenSSH). I would mention to FileCOPA that the problem only occurred when you upgraded to 10.11, and that it would be a good idea for them to test compatibility with 10.11 (i.e. with OpenSSH_6.9p1).

    Thanks,

    Jim Matthews
    Fetch Softworks

    Posted 1 year ago #

  • Steven Member

    Jim, latest message ex FileCOPA: "We updated a Mac to OSX 10.11.2 and it still works flawlessly."

    Does that change anything from your perspective ?

    Cheers.

    Posted 1 year ago #

  • Jim Matthews Administrator

    That's a good data point to have. Would it be possible for me to try to connect to your server? You could send me the hostname at http://fetchsoftworks.com/fetch/feedback . I don't think I need a username or password.

    Also, are you logging in with a password, or with a public key?

    Thanks,

    Jim Matthews
    Fetch Softworks

    Posted 1 year ago #

  • Steven Member

    Jim, have sent you the info via http://fetchsoftworks.com/fetch/feedback

    Regards whether password or public key, I'm not sure what public key is, but I do enter user name and password.

    Posted 1 year ago #

  • Jim Matthews Administrator

    Steven and I have researched this problem and come up with a workaround. If you are trying to connect to a FileCOPA SFTP server from OS X 10.11 El Capitan, and the connection is always dropped, you can try entering the following in Terminal:

    echo -e "\nHost HOSTNAME\nKexAlgorithms diffie-hellman-group14-sha1\n" >> ~/.ssh/config

    replacing HOSTNAME with the hostname of the server you are trying to connect to. This command configures your Mac's ssh software (which is used by Fetch) to choose a particular key exchange algorithm when connecting to HOSTNAME. Doing so appears to work around a bug in the FileCOPA SFTP server.

    Note: I recommend not trying this workaround unless you are sure the hostname is running the FileCOPA SFTP server software, and you've already tried contacting FileCOPA support about the problem.

    I've passed on the results of our research to FileCOPA, so hopefully they will fix this problem on their end before long.

    Thanks,

    Jim Matthews
    Fetch Softworks

    Posted 1 year ago #

  • Steven Member

    A public thank you to Jim Matthews for his tenacity and interest in resolving this issue.

    Posted 1 year ago #

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