[lug] Multiple Questions

[Shannon M. Johnston]

Alright please bear with me...
I'm going to be doing a major reconfiguring of an ISP and there are some
areas that I'm a bit shady.
1.) Any advice on the setup and use of qmail will be appreciated. (I
heard it was better than sendmail.)
2.) I'm going to be reloading linux on a main server. Is there a way to
keep all of the user accounts and passwords?
3.) Has anyone had experience with port sentries? Could you share
information with me?
4.) Is there anything special I have to do in order to disable ports? I
don't want some services running on some computers and I don't want
access through the ports.
5.) Any tips/info on configuring NFS would be great.

Sorry for all the questions... but any help on these issues would be
great!
In order to save people's bandwidth, please reply to:
nunar at mauromedia.net

Thanks,
Nunar