After you have determined that basic connectivity still exists, the next step is to determine the scope of the problem.
After all, if the problem ends up being something as simple as a NIC failure, you can save yourself a lot of time by checking for the problem up front.
The easiest way to verify connectivity is to log on to the DNS server and try to ping a few machines.
You should also try to ping the DNS server from a few random machines.
Remember that ping will work only if you allow ICMP packets through the firewall on the machine you are pinging.
Another thing to look at is whether the problem affects all of the users on the network or it's limited to a subset of users.
If you determine that only some users are affected, check to see whether all those users are located on a common network segment.
If so, the problem could be related to a router failure or a DHCP configuration error.
DNS is one of the most essential services on any Windows network.
Active Directory can't function without DNS, and it's is also used by any number of other network functions.
So it's critical to troubleshoot DNS problems as fast as possible. Here are10 of my favorite DNS troubleshooting techniques.
When DNS problems occur, one of the first things you should do is verify that the DNS server still has network connectivity.