About DNS Records
Since DNS server plays an important role when it comes to keeping the network up and accessible, it becomes important for the administrators to keep a close eye on the DNS records, and verify their validity on a regular basis. DNS records are the entries of the computer names along with their corresponding IP addresses in the DNS server database. Although there can be several DNS record types that a DNS server database can have, some of the most commonly used and important DNS records include:
- Host (A) – Host (A) records are the names of the computers along with their corresponding IPv4 IP addresses that are registered with the DNS server.
- Host (AAAA) – Host (AAAA) records are the names of the computers along with their corresponding IPv6 IP addresses that are registered with the DNS server.
- MX – MX are the Mail Exchanger records that are added to the DNS server when Microsoft Exchange Server is deployed in the network.
- CNAME – CNAME a.k.a. Canonical Name is an alias name that administrators create in the DNS server to specify a more user-friendly name of any computer that has a complex name. For example, if a Fully Qualified Domain Name (FQDN) of a file server in the network is ‘fs01-dom01-comp05.mydomain.com’, administrators can create ‘fileserver.mydomain.com’ as a CNAME (alias name) for that fileserver.
Importance of Adding DNS Records Manually
While working in production environment, where the computers connected in the network contain highly sensitive and classified information, administrators must consider the security of the network at the topmost priority. Although any such network infrastructure is already protected by strong firewalls and highly efficient anti-virus applications, most administrators still add an additional layer of security to the network by disabling DNS dynamic updates. When DNS dynamic updates are disabled, no computer from within the network or from outside can automatically register itself with the DNS server, thus preventing the server from adding fake and unwanted DNS records automatically.
Although the above discussed DNS configuration increases the network security, it also increases the administrative overhead because administrators are then required to add the DNS records of authentic computers in the network manually. Experienced administrators can also use batch files to automate the process of adding multiple DNS records just by a single click.
Add Host (A) DNS Records Manually
To add Host (A) DNS records manually to the DNS database, administrators must follow the steps given as below:
- Log on to Windows server 2008 R2 DNS server computer with domain admin or enterprise admin credentials.
- From the desktop screen, click Start.
- From the Start menu, go to Administrative Tools > DNS.
- On DNS Manager snap-in, from the console tree in the left pane, double-click to expand the DNS server name.
- From the expanded list, double-click Forward Lookup Zones.
- From the displayed zones list, click to select the DNS zone for which Host (A) DNS record is to be added.
- Once selected, right-click the DNS zone.
- From the displayed context menu, click New Host (A or AAAA).
- On New Host box, type in the Fully Qualified Domain Name (FQDN) along with the IP address of the target host computer in the Name (uses parent domain name if blank) and IP address fields respectively.
- Once done, click Add Host. Optionally, Create associated pointer (PTR) record checkbox can also be checked to automatically generate a PTR entry of the target computer in the Reverse Lookup Zones before clicking Add Hostbutton.
- On the displayed message box, click OK.
- Back on the New Host box, click Done.
- Close DNS Manager snap-in when done.