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dotConnect for MySQL says: "Can't connect to SSH server on 'xxxx.com': Server does not support diffie-hellman-group-exchange-sha256 for keyexchange"

Yet, I can connect to the SSH server using other software which do not depend on dotConnect for MySQL. For example, Putty, MySQL Workbench, and Navicat all work fine connecting with the SSH server and MySql databases.

update 5/24/2017 -
sudo grep Kex /etc/ssh/sshd_config
KexAlgorithms diffie-hellman-group-exchange-sha256
This is definitely enabled.

I get the same error using Toad for MySQL, Red Gate's MySQL Compare and MySQL Data Compare . . . All of which use dotConnect for MySQL.
end update 5/24/2017

Suddenly, can't connect to SSH server using Red Gate's MySQL Compare and MySQL Data Compare which were working well for several days. According to Brian Donahe at Red Gate the connection is managed by Devart's dotConnect for MySQL DevArt.Data.Mysql
Suddenly I now get the below error message which I suspect is itself potentially misleading. I'm hoping someone may have seen this behavior before and suggest what I might do to solve.

Background:

I had previously been successfully using both MySQL Compare and MySQL Data Compare via their SSH user interface accessing databases residing on 2 separate domains/machines.

Now neither program can connect to SSH server on either of the machines and produce the error.

Clicking on Compare Now button produces . . .

MySQL Compare - Aborting Can't connect to SSH server on 'xxxx.com': Server does not support diffie-hellman-group-exchange-sha256 for keyexchange

Additionally, MySQL Data Compare produces the below popup message . . .

Connection Population Error Unknown exception: Can't connect to SSH server on 'xxxx.com': Server does not support diffie-hellman-group-exchange-sha256 for keyexchange

Clicking on the Database button to populate the drop-down list produces . . .

Error fetching database list Error connecting to database Can't connect to SSH server on 'xxxx.com': Server does not support diffie-hellman-group-exchange-sha256 for keyexchange

I'm hoping someone may have seen this behavior before and suggest what I might do to solve.

This functionality should be supported in the next version of dbForge Data Compare for MySQL.

alexa wrote:This functionality should be supported in the next version of dbForge Data Compare for MySQL.

That's great. However, I think we're off track. The error message say Server does not support diffie-hellman-group-exchange-sha256 for keyexchange. However, the server does.

If I may ask, please take another look at my original post.
Again, it was working fine and then suddenly started producing the error message.
Thank you for any help you can provide.

Thank you for bringing this to our attention.

The fix will be included in the next product build that should be released this week.

We would like to let you know that we have released dbForge Data Compare for MySQL, v5.1.17 where the issue you reported is fixed https://www.devart.com/dbforge/mysql/da ... nload.html

Thank you for your help in improving dbForge Data Compare for MySQL.