You may have different issues in DNS service such as DNS sever not responding to the clients or DNS server does not resolve the names correctly. Here I have some of the steps that will help you to troubleshoot and resolve some of the common issues.

As you know the connectivity issues between the host and server is most important part, you should make sure that there are proper connectivity between client and DNS server. First, check that related client hardware (cables and network adapters) are working properly at the client by using basic network and hardware troubleshooting steps.

If you have configured to obtain the IP address and DNS address automatically(Using DHCP) you can release those details and request for a new configuration. There are chances that your IP address may have conflict in your network or the details of DNS server is old, performing the below action will release the details and  obtain the details once again.

Please use  ‘nslookup’ to check whether the DNS resolve the name.

There are chance that your zones are configured and kept to pause on DNS server make sure that it is started.

Right click reverse lookup zone that is existing in DNS console and select ‘properties‘->Under general tab make sure that the ‘status‘ as running. If not ‘start’->Apply->OK.

              4. Make sure that DNS server is not using a nonstandard configuration

As you know the default DNS server port is UDP 53 all queries using ‘nslookup’ will be listen through this port.  If the DNS server is located on another network and is reachable only through an intermediate host (like a router or proxy server), the DNS server might use a nonstandard port to listen for and receive client requests. So make sure that none of the intermediate firewall or proxy server configuration is intentionally used to block traffic on well-known service ports that are used for DNS. If not, you might be able to add such a packet filter to these configurations to permit traffic to standard DNS ports.

DNS servers uses the recursionprocess to resolve the names that are not located within the configured DNS domain name that is used by the DNS servers and clients. Hence we can confirm that server has a problem with its ability to correctly perform recursion.

For recursion to work successfully, all DNS servers in the path of a recursive query must be able to respond to and forward correct data. If not, a recursive query can fail for any of the following reasons:

Check whether the DNS server can use both forwarders and recursion. By default, all DNS servers are enabled to use recursion, although the option to disable its use is configurable in DNS Manager to modify advanced server options. The other possible situation in which recursion might be disabled is if the server is configured to use forwarders and recursion has been specifically disabled for that configuration.

Test for connectivity to the root servers. If root hints appear to be configured correctly, verify that the DNS server that is used in a failed query can ping its root servers by IP address. If a ping attempt to one root server fails, it might indicate that an IP address for that root server has changed. Reconfiguration of root servers, however, is uncommon. A more likely cause is a full loss of network connectivity or in some cases, poor network performance on the intermediate network links between the DNS server and its configured root servers. Follow basic TCP/IP network troubleshooting steps to diagnose connections and determine whether this is the problem.

There are chances you your dynamic updates are not working and issue with your zone. Use the below MS link to troubleshoot those issue.

For Dynamic updates: http://technet.microsoft.com/en-us/library/cc770822.aspx

For zones: http://technet.microsoft.com/en-us/library/cc731210.aspx

Verify that the server computer has a valid functioning network connection. First, check that related client hardware (cables and network adapters) are working properly at the client by using basic network and hardware troubleshooting steps. If the server hardware appears to be prepared and functioning properly, check that it has network connectivity by using the ping command to contact other computers or routers (such as its default gateway) that are used and available on the same network as the affected DNS servers.

nslopkup is one of the CLI tool that will help you to analyze the DNS queries. You can make use of this by command prompt. This tool will help you to analyze the and verify that name resolution is working. Secondly, if name resolution isn’t working, it allows you to confirm which DNS server is being used.

Please make use of the below link to have more idea about using nslookup.

Most organizations have at least two DNS servers. If your primary DNS server is having problems, try using an alternate. If name resolution begins working after you switch DNS servers, you have confirmed that the problem is indeed related to the DNS server and not to some external factor.

Try to reboot the DNS server and check whether it help you to resolve the issue.