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:
1. Log on to Windows server 2008 R2 DNS
server computer with domain admin or enterprise admin credentials.
2. From the desktop screen, click Start.
3. From the Start menu, go to Administrative
Tools > DNS.
4. On DNS Manager snap-in,
from the console tree in the left pane, double-click to expand the DNS server
name.
5. From the expanded list, double-click Forward
Lookup Zones.
6. From the displayed zones list, click to
select the DNS zone for which Host (A) DNS record is to be added.
7. Once selected, right-click the DNS zone.
8. From the displayed context menu, click New
Host (A or AAAA).
Click
New Host
9. 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
addressfields respectively.
10. 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.
Add
a Host
11. On the displayed message box, click OK.
12. Back on the New Host box,
click Done.
13. Close DNS Manager snap-in
when done.
