update 5/24/2017
sudo grep Kex /etc/ssh/sshd_config
KexAlgorithms diffie-hellman-group-exchange-sha256
This is definitely enabled.
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. 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
The connection is managed using a third-party component from another company named Devart (according to this source and confirmed here by Brian Donahue at Red Gate that it is Devart's dotConnect for MySQL https:// forums.devart.com/viewtopic.php?f=2&t=29052&p=99554#p99554 ).
I'm hoping someone may have seen this behavior before and suggest what I might do to solve.
