"I for one have no particular problems with the fact that Nessus
has gone to a closed source model from version 3, with the
exception that this means I can't run Nessus on some of my
platforms of choice (i.e., Gentoo Linux). However, since a package
is available for Debian 3.x, I wondered if it would work on Ubuntu.
This didn't prove too difficult--I expect because Ubuntu is based
on Debian 3.x and also because the Nessus developers have
historically bundled their own versions of libraries to prevent
library dependency issues (that seems to be the usual reason for
not being able to install Debian packages on Ubuntu for me)..."