I have DC window 2008,it does include DHCP server, I surprised by all users they are not getting any IP address, Despite the event viewer doesn't?

make sure multiple dhcp server is configured in same network

It depends upon the situation, that any one situation would be:

• Changed IP address on DHCP server and now clients cannot get IP addresses.

• DHCP clients across router from DHCP server are unable to get an address from the server.

• Multiple DHCP servers exist on the LAN.

For the best answer please see link below

https://support.microsoft.com/en-us/kb/197197 

first for the DNA is very important for code

ip is the device on the Internet figure

mac is your network card and placed by the manufacturer in the sense that the card network existing device has a number does not repeat with another device in the world and consists of 32 bit which is a trademark are owned by the organization I EEE So the bottom line is Alai PII possible change in it but the Mac is difficult because it is fixed.

Make sure the DHCP Server set to active and set into the same ntwork

you should to check the below:

adding the dhcp IP server on the switches which the users are connected to it physycally through " on cisco for example IP helper".

check the connectivity of any existing firewall between user zone and server zone.