How to setup Nessus 3 under CentOS 5

• download Nessus server and command line tool 'nessus', it should be binary rpm package. After you registered, it will provide a link to download.
• For running a GUI client, you need to download NessusClient (a GUI client for Linux/Windows Nessusd), it's rpm package too
  
• Automatic plug-in update

1. run the following command to check whether you registered or not

# /opt/nessus/bin/nessus-fetch --check
You should obtain the following output:
nessus-fetch is properly configured to receive a direct feed or
nessus-fetch is properly configured to receive a registered feed

2. after registeration, you should receive activation code for the Nessus plugin feed through email, follow the instruction in email to activate your installation, you can register online or offline

3. use the following command to auto update plugin
/opt/nessus/sbin/nessus-update-plugins -v
4. make sure option 'auto_update' is set to yes in /opt/nessus/etc/nessus/nessusd.conf (this is the default)

• generate SSL certification

# cd /opt/nessus/sbin
# ./nessus-mkcert
answer questions to generate SSL keys
# ./nessus-adduser

• start up NessesClient

# cd /opt/nessus/bin
# ./NessusClient
note: edit server to specify the username and password you typed in above 'nessus-adduser' command.

• command line mode

# cd /opt/nessus/bin
# ./nessus -q -T html localhost 1241 nessus nessus /tmp/target /tmp/result.html