====== SSH ======
===== sudo aptitude install =====
''openssh-server''

===== Running SSH on non-standard port =====

  - ''/etc/ssh/sshd_conf'' → Parameter "Port"
  - ''/etc/init.d/ssh restart''

===== Login on non-standard port ssh system =====

''ssh -p <port> <user>@<server>''


===== SSH Client ====
Following lines create config file, which enables X forwarding. -X doesn't need to be typed anymore. In addition to that it forces the client to send a keep alive packet every 5 seconds.

<code>
cat >.ssh/config
Host *
ForwardAgent yes
ForwardX11 yes
ServerAliveInterval 5
</code>
ctrl+c finishes operation.

===== Remove hostkey from known_hosts ====

<code>ssh-keygen -R <host></code> removes the hostkey of <host> from ''~/.ssh/known_hosts''.

===== SSH Tunnel (e.g. for remote MySQL)  =====
  - ''ssh -N -L 3307:<remotehost.com>:3306 <ssh_login>@<remotehost.com>'' or sometimes ''3307:localhost:3306''
  - ''mysql -u<mysql_login> -p -P 3307 -h127.0.0.1'' 

Aternative Way:
''ssh -C -f -L 3307:localhost:3306 <ssh_login@remotehost.com>@<remotehost.com> sleep 10; mysql -u<mysql_login> -p -P 3307 -h127.0.0.1''

This creates a auto-closing tunnel with compression (-C) enabled.