MacOS/GoDaddy ssh error: Unable to negotiate, no matching host key type found, their offer

As a quick note, I haven’t tried to log into one of my GoDaddy websites in several months, and when I tried to log in just now I got this macOS ssh error message:

Unable to negotiate with <ip-address here> port 22: no matching host key type found. Their offer: ssh-dss

The short answer to this problem is that macOS Sierra uses OpenSSH 7, and it doesn’t use old technologies like the ssh-dss (DSA) public key algorithm. The OpenSSH “legacy technology” web page states, “It too is weak and we recommend against its use.”

MacOS/GoDaddy ssh-dss solution

If you have to use it — such as when GoDaddy controls the Linux servers — you can use this ssh command to log into a server that uses ssh-dss:

ssh -oHostKeyAlgorithms=+ssh-dss

That solved my problem and I was able to log into my GoDaddy Linux server using ssh-dss.

For more information about this problem and the solution, see the OpenSSH legacy web page.