Learning Linux RedHat 7.0 - mail and firewall server

[Jorge_Beteta]

Hello experts!
Where can I get some on-line manuals about maintaining Linux RedHat 7.3 server, installing and configuring mail server and firewall on Linux RedHat?
I'm newbie in this operating system, but I need to become an expert very soon! I have good experience with SCO Unix.

Which mail server is the best for RedHat 7.3?

Many Thanks

[Dolda2000]

First, let me start off with saying that I really appreciate you emerging from SCO to Linux; SCO is a cockroach that deserves to die. Just my personal opinion, though. ;-)

Which mail server that is the best naturally depends on your needs. However, to find manuals and HOWTOs, TLDP is always the best. Also, to learn to set up a firewall, check out the iptables/netfilter documentation on http://www.netfilter.org/. There is also the manpage on iptables(8), which does such a good job of describing the interface that you can understand the underlying architecture from it.
RedHat also stores all their manuals online at http://www.redhat.com/docs/.

And as well, if you're wondering about something, you can, of course, always ask here.