Christiaan Welvaart cjw@daneel.dyndns.org writes:

When I try to initiate a session using MidpSSH [1] I get: Protocol error: No common hostkey algorithm.^M What could be causing this, or how can I debug the problem?

The first thing to do is to figure out which host key algorithm(s) each side is advertising. On the lshd side, you could use --debug and look at the KEXINIT messages (I don't think --verbose displays any information when the negotiation fails, which could be considered a bug). There's probably some similar option for the MidpSSH client.

From the source code and the RFC I see that the hostkey algorithm is pretty much always ssh-dss, so maybe the real problem is somehwere else.

That's not quite true. It depends also on the configuration.

For example, if the server process has been configured with an RSA host key and no DSS keys, then it will advertise only ssh-rsa. And if a client that supports only ssh-dss tries to connect to that server, then communication fails with "No common hostkey algorithm".

Regards, /Niels