DNS delegation and DNS tools

DNS delegation is used if you want to point to a DNS subdomain zone being administered by someone else. Make sure that the name server record of the server exists on the server where the DNS of the subdomain resides. Then you right click on the zone - Choose new delegation - Click next- Type the delegated domain- Click next- Click add and type the FQDN of the server where the subdomain resides- Click Ok and Ok again.

Now if anyone wants to resolve again the subdomain- it points to the Nameserver record in the zone of the primary server. Once it points to that server it looks for the record in the subdomain on the pointed server and resolves the query using that.

DNS TIP: In case if you are not able to resolve internet queries but the intranet queries work fine, the reason can be that someone has created a .(root) zone on the DNS server.

dnscmd /zoneexport infoit.com.au infoit
This command will export all your zone info to the file named infoit for zone infoit.com into C:/windows/system32/dns/infoit

dnscmd /createdirectorypartition app1.infoit.com.au

To check use
dnscmd /enumdirectorypartitions

Now, to replicate this newly created partition to server2 only and not the whole AD, use
dnscmd server2 /enlistdirectorypartion app1.infoit.com.au

To delete this newly created directory partition,
dnscmd /deletedirectorypartition app1.infoit.com.au

DNS Basics

DNS is used to translate the ipaddresses to names. To explain, how DNS works, please look at the diagram on left. There is a DNS client which is also known as resolver. If DNS Client needs to resolve admin.server2.com it will check its client cache for which it used HOSTS file. It is usually in

C:/>Windows/System32/Drivers/etc/

If the record is not found in that file, it looks for a dns server. You enter that under the IPv4 properties for the network adapter.

When it find the DNS server, the server looks for the record in the server cache. Cache.dns file is located in the server at the following location

C:/>Windows/System32/DNS/

If it does not find the entry on the root hint file, it goes on the internet and looks for the "." Once that is resolved, "." server will resolve for the ".com" server. In same way the ".com" server resolves for "server2.com" and in turn the "student.server2.com" address gets resolved. This all happens on UDP PORT 53. If there is another DNS server in and the zones have to be transferred, it used TCP PORT 53 to transfer.

There are two types of queries:

1. Recursive: When the server HAS to resolve the query

2. Iterative: When the server can look for other servers, if it cannot resolve the query