Can anyone help me build my own mail server?
 

Please help me build my own mail server on slackware..

using

Postfix
Dovecot
and
Squirrelmail

please..

Help you with what, really?? You haven't said what you've done/tried, or what problems you're having. If you need how-to guides, then the first thing you should do is go to Google, and put in things like "slackware postfix howto", and "slackware dovecot howto". Or just visit the Postfix, Dovecot and Squirrellmail pages, and read their installation instructions.

If you get stuck, we'll be glad to help you if you post specific questions....but there's not much we can help you with, based on what you've asked.

If postfix is installed, you might take a look at a couple of README files on your system. Go to /usr/share/doc/postfix*/README_FILES/ and look at BASIC_CONFIGURATION_README and STANDARD_CONFIGURATION_README. There are other README files in this directory, but those two should give you a good start.

Mike

hmmm
 

another question is that is there any specific folder for each package? or i can put it anywhere?

i haven't installed any of it yet..

Setting up a mailserver, is a quite heavy task. There are a LOT of things to think about.
I would recommend you to take small steps first, if this is all new to you.

Remember to create MX records on your domain, if you want this to work in the real world.

1) Install and configure postfix, to get it up and running, with or without MySQL as backend! When you can send and recieve mails flawlessly, proceed to the next step, which would be dovecot in your case. Note that you can recieve e-mails fine by checking the logs without dovecot.
2) Install and configure dovecot.
3) Install and configure squirrelmail. Should be the easiest part, since it almost runs out of the box, at least on Debian. :)

Good Luck.

Klaatu did a podcast on this topic. He talks about sendmail, not postfix, but it could be a nice primer.

It's episode 5x06 at this link:

http://thebadapples.info/index5.html

Well, if you read the installation instructions for any of the pieces of software you mentioned, you'd find that out. If you install such things from pre-built package, then it'll be installed in a 'default' location, which varies by the piece of software. If you build from source, you'll be able to install it wherever you choose.