Issue with a default installation of Ubuntu 11.04

[vpslist]

aptitude is not default, so maybe a check to see if aptitude is on the system?

Debian 6, aptitude is default.

[Mins]

Ah, that's a good suggestion.
I'll add a line to install aptitude before starting the rest of the setup.

[vpslist]

Definitely some prereq checks would be solid when running the installer. I have not put this into production yet but I will and probably mention it on vpslist.net

[Mins]

Thanks! Added a line to install aptitude for the latest commit.

It'll be a good idea to trial this mail stack before pushing to production, specifically the rejection rules (smtpd_recipient_restrictions for postfix's main.cf).
It may be too strict for the vast majority of poorly configured mail servers.