SSH Key Exchange Isn't Working
Problem: At one site, I had the .ssh/authorized_keys file set up, but the server constantly challenged for the login password.
Solution: The problem turned out to be that the
sshd_config file didn't have a correct pointer to the SSH V2 host keys, meaning that we were only getting a SSH V1 session (detected by running
ssh -v user@remotesystem and also invoking
sshd with the -d flag). Since key exchange is a function of V2, it obviously never worked :) Correcting the entries
HostKey /usr/local/etc/ssh_host_rsa_key
HostKey /usr/local/etc/ssh_host_dsa_key
fixed the problem.