The contents of this how-to have been contributed by Dr. Patrick Marlier and Dr. Anita Sobe. 

1. Download putty from http://www.putty.org
2. Use puttygen to convert your ssh key file to a ssh keyfile that
   putty understands.
3. Start putty
4. Session -> Host Name -> the_hostname_you_login_into
5. Connection -> Data -> Login details -> Auto-login username -> your_username_here 
6. Connection -> Proxy -> Proxy type -> Local
7. Connection -> Proxy -> Proxy hostname -> clusterinfo.unineuchatel.ch
8. Connection -> Proxy -> Username -> trampoline
9. Connection -> Proxy -> Telnet command or local proxy command
   plink %user@%proxyhost -i unine.ppk  -nc %host:%port n
   unine.ppk is the filename of my ssh key
   plink is in the same directoy as putty.exe
10. Connection -> SSH -> Auth -> Private key file for authentification:
    Browse to your private ssh key file (if your internal machine is using
    ssh key based authentification).