nessus is an X11 client based on the Gimp ToolKit (GTK).
This man page explains how to use the client.
The nessus client interface is divided in several panels:
* You can restrict the maximum number of hosts to test using the ``Max Hosts'' entry. This is a feature that prevents you from scanning too many machines; or accidentally scanning other machines. (For instance, if you only plan to test prof.fr.nessus.org and www.fr.nessus.org, you can safely set this entry to ``2'').
* This panel also allows you to enable the ``Perform a DNS zone transfer'' option. This option is dangerous and should be enabled with caution. For instance, if you want to test www.nessus.org, then if this option is set, nessusd will attempt to get the list of the hosts in the ``nessus.org'' domain.
This option may be dangerous. For instance, if you enable it and you ask to test 192.168.1.1/24, then nessusd will do a reverse lookup on every IP, and will attempt a DNS zone transfer on every domain. That is, if 192.168.1.1 is www.foo.bar, and 192.168.1.10 is mail.bar.foo, then a DNS zone transfer will be made on the domains ``foo.bar'' and ``bar.foo''.
% More examples should be included here (jfs)
Several other people have been kind enough to send patches and bug reports. Thanks to them.