I am a microsoft guy who wants to move away from Bellsouth email servers to mandrake 8.1 using sendmail and hosting our three domains.

I've completed my Mandrake install and have the box talking to my network. My next questions are as follows:

1) Does sendmail work with Outlook? From what I have read on the internet I would say yes, but not sure. Any helpful links or thoughts? Issues I should know about before committing?

2) Any helpful links for the installation of sendmail? I have scoured the net but found only a few that are very technical and I was hoping for more GUI commands as opposed to linux prompt.

3) Will sendmail host 3 different domains with 30+ users at each domain (about 90 in all). I want to set them up as POP3 son they can use OUtlook as stated above.

4) How do I open both SSH ports for telnet and FTP and the appropriate ports for email and webhosting?

Thanks in advance and I am very interested in learning more about Linux from all of you!

KDE is the GUI I am using!

I'm quite the newbie, but the easiest way I've found to make configuration changes (from a gui) is via webmin (www.webmin.com). Not only can you make Sendmail configuration changes, but you can make changes to your firewall for the ports in question.
I'm still running the Sendmail build that came with Red Hat 9. I don't have the hang of patching, installing, etc. ... yet.
For Red Hat, I read a post about enabling POP3. All you had to do was go to the "ipop3" file, change "disable" to "no" and restart "xinetd". Of course, you still have to open the FW for POP. No, I haven't tested this yet.

Good luck.
Chase