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I'm using UltraEdit (Windows) to edit files on remote SFTP servers. For some reason I can no longer connect to one of those servers.

Here's what was changed:

  1. The server was moved (and updated) from one VM to another - usually this only prompts about rsa fingerprint changed and then works with no other changes needed.
  2. I've been trying out different software for mapping SSH/SFTP as a Windows drives.

The connection seemed to break after mapping the server in ExpanDrive (I'm almost certain that I continued working on the server after it was moved and updated).

Some points worth noting:

  • The problem only exists for this particular server as I can still connect to the other VMs (which are in the same network and have the same requirements to log in).
  • I can still connect to the server with PuTTY (after updating rsa fingerprint)
  • FileZilla SFTP also works as well
  • Some driver mappers work (SFTP Net Drive, sshfs), some don't (ExpanDrive, WebDrive)
  • I've removed all entries containing the server name in the registry.

Faulty server info

  • Linux titan 3.16.0-4-amd64 #1 SMP Debian 3.16.7-ckt11-1+deb8u3 (2015-08-04) - x86_64 GNU/Linux
  • Distributor ID: Debian
  • Description: Debian GNU/Linux 8.1 (jessie)
  • Release: 8.1
  • Codename: jessie

Info from working server

  • Linux ymer 3.2.0-4-amd64 #1 SMP Debian 3.2.68-1+deb7u1 x86_64 GNU/Linux
  • Distributor ID: Debian
  • Description: Debian GNU/Linux 7.8 (wheezy)
  • Release: 7.8
  • Codename: wheezy

Any idea what could be causing the connection issue in UltraEdit/drive mappers?

Woodgnome
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  • Do you perhaps get some kind of error? Are you trying to use diffie-hellman group exchange instead of group 14? – Falcon Momot Sep 07 '15 at 07:44
  • ExpanDrive has magically started working. WebDrive claims my username/password credentials are wrong and UltraEdit immediately shows error connecting, no error message (also when using the SSH console). So TL:DR: No error message (that I can find). How can I check which diffie-hellman the servers use? – Woodgnome Sep 07 '15 at 08:01
  • It's which key exchange method the clients specify that counts, so it depends on the client. Newer versions of openssh choke if you try to negotiate DH group exchange. – Falcon Momot Sep 07 '15 at 08:03

3 Answers3

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Found out that my home computer has the same issue and I definitely did not mess around with SSH drive mappers there, so the issue had to be related to the server upgrade.

I am running UltraEdit v20.00 - tried running a trial of v22.10 which solved the issue.

I assume there are some SSH changes in the newer Debian version which are not supported by UltraEdit v20.00, but fixed in a later version (probably v21.30, see http://www.ultraedit.com/products/ultraedit/latest-changes.html "...improvements and fixes to the following: FTP/SFTP").

Most likely the same issue that prevents me from mapping drives in certain applications.

Woodgnome
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I had a similar issue whereby Filezila could connect to my server, but my old copy of WebDrive couldn't.

Looking at the server logs in /var/log/auth.log I could see this error message:

sshd[1345]: Unable to negotiate with x.x.x.x port 54862: no matching cipher found. Their offer: aes256-cbc,twofish256-cbc,twofish -cbc,aes128-cbc,twofish128-cbc,blowfish-cbc,3des-cbc,arcfour,cast128-cbc [preaut h]

I solved this by enabling those legacy ciphers in sshd_config, but this was only a development server, I wouldn't recommend that for a production server.

Matthew Lock
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Hmm dont know if that would help you or not but I started using SysaxAutomation. They have a server modul and a script editor which comes with SFTP and anything you could do with FTP.

Steven
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