Once the TTL duration of the host record expires, the record is automatically removed from the DNS cache of the DNS client computer. When this happens, the DNS client computer is required to resend the DNS query to the DNS server in order to resolve the same IP address if it wants to communicate with the DNS client computer again.
By increasing the TTL duration, the DNS administrators can extend the time duration for which resolved DNS query can remain in the DNS client computers’ DNS cache.
Here is how you can configure the Time To Live (TTL) period for the DNS records after which they automatically get removed from the DNS cache of the DNS client computers:
- Log on to the Windows Server 2012 DNS server using the Enterprise Admin or Domain Admin account credentials.
- If not already started, initialize the Server Manager window from the bottom left corner of the screen.
- Once the Server Manager window is initialized, from the left pane, click to select the DNS category.
- From the right pane, under the SERVERS section, right-click the DNS server.
- From the context menu that appears, click DNS Manager.
- On the opened DNS Manager snap-in from the left pane, expand the server name (DC-01.MYDOMAIN.COM for this demonstration), and then expand Forward Lookup Zones.
- From the expanded list, click to select and then right-click the domain name. (MYDOMAIN.COM for this demonstration.).
- From the displayed context menu, click the Properties option.
- On the opened domain’s properties box, go to the Start of Authority (SOA) tab.
- On the displayed interface, in the TTL for this record field, change the second value from the left (hours) from the default ‘1’ to ‘5’.
- Once done, click OK to save the changes and to close the domain’s properties box.
- Back on the DNS Manager snap-in, right-click the server name. (DC-01.MYDOMAIN.COM for this demonstration.).
- From the displayed context menu, go to All Tasks, and click Restart from the submenu that appears.
- Wait till the DNS service restarts before the DNS server starts working using the modified settings.