Excjange Server 2003

Hi...plz i want to know when and why we use exchange server (2000 or 2003) .......and the another question is when we use DHCP and DNS thank u all............Ma'en

Welcome to f.cx

For your first question refer this link
www.microsoft.com/exchange/evaluation/whatis.mspx

For your second server on DNS read
www.firewall.cx/dns-intro.php

For your third question
DHCP(Dynemic Host Configuration Protocol) read
en.wikipedia.org/wiki/Dynamic_Host_Configuration_Protocol

Enjoy your stay.

Enjoy..

~Pranav