Nessus

installation:
- go to http://www.tenable.com/ and download the client package and install it.
- run sudo /opt/nessus/sbin/nessus-adduser to add a user.
- register at http://www.tenable.com/ to get a free activation key.
- run /opt/nessus/bin/nessus-fetch --register <your key# here> to register the client.
- run /etc/init.d/nessusd start to start the server.
- access the web interface by going to https://127.0.0.1:8834/