If when SSHing to a server you receive an alert that the host dsa key for the SSH server does not match the fingerprint listed in ~/known_hosts, the finger print can be checked providing you have physical access to the server or another connection is already open:

ssh-keygen -l -f /etc/ssh/ssh_host_dsa_key.pub

Run this on the server you are trying to connect TO and compare the output to that given from the ssh client.