==== no matching host key type found ====
error
<code>
$ ssh hostname -l username
Unable to negotiate with <IP address> port 22: no matching host key type found. Their offer: ssh-rsa,ssh-dss
</code>

workaround
<code>
ssh -oHostKeyAlgorithms=+ssh-dss hostname -l username
</code>

==== copying keys ====
When setting up password less authentication via ssh, use ssh-copy-id to copy the public key to the remote machine.

The command looks like
<code>
ssh-copy-id user@host
</code>
When you run it the first time, it will ask for password and then copies the key to the remote machine. It is very convenient!

Ref:
  * man page - https://linux.die.net/man/1/ssh-copy-id

==== Useful links ====
  * https://linuxize.com/post/using-the-ssh-config-file/ - Using the SSH config file
    * Well written; easy to follow; high information density; non-trivial examples

  * [[http://www.linuxproblem.org/art_9.html | ssh without password]]
  * You can create nicknames for logging into remote servers in ~/.ssh/config and can use them with ssh, rsync, scp etc., - https://www.saltycrane.com/blog/2008/11/creating-remote-server-nicknames-sshconfig/