To Add DNS zone entry in Windows Server.

1. rdesktop login to windows server.
2. To open DNS Manager go to "Start Menu >> Administrative Tools >> DNS "

or Go to run >> type in dnsmgmt.msc

3. In DNS Manager go to "Forward Lookup Zones" and right click on top of the "Forward Lookup Zones" folder to open menu and select "New Zone" and then
>> Select the Zone type
>> Enter the zone name. Eg : domain.com
>> Select "Create a new file with this file name"
and complete the zone wizard.

4. Now to add entries to zone file

In DNS Manager go to "Forward Lookup Zones" and find the domain name and click select the domain.
>> Then on the right side of the DNS Manager you could see the entries in the zone db file of the domain.
>> Right click open the menu and you could see the enties to add MX,NS,A record etc.

5. Once the entries are made, right click on domain name under the "Forward Lookup Zones" and reload the domain zone file.