Diagnosing DNS resolution problems
Posted by RAJU K, Last modified by Rupi Singh on 22 July 2015 12:29 AM
Diagnosing DNS resolution problems.
If you are encountering problems when resolving particular domain names/web sites, and want to verify whether the problem is with your DNS, please try running the following diagnostic procedures.
Step 1: Verify that your ISP DNS resolving your web site properly.
At the command prompt, run any one of the following commands, where hostname is the name that you were having difficulty resolving:
Try with ISP DNS Resolver:
> nslookup hostname
If the last line shows IP address, then your ISP dns working fine.
Now try with Google/Public DNS:
nslookup hostname 188.8.131.52
nslookup hostname 184.108.40.206
The above test uses Google Public DNS resolver instead of your ISP. So you can quickly check DNS resolving problem without changing DNS IP addresses.
If you are not able to get a successful result, this means that there is most likely a problem with the server you are trying to contact. Wait some time and try running the tests again. This may be a temporary problem on the server's side that will likely resolve itself eventually. If it does not, you should contact by opening helpdesk ticket.
Step 2: Verify that your client can communicate with the FastWebHost servers.
Open a command prompt, and run the following command:
cmd> tracert -d 220.127.116.11
If the last line of the output does not list 18.104.22.168 as the final hop, or if there are significant timeouts, there may be a network problem preventing you from contacting our servers. Please include the output of the command in any communication with the FastWebHost Team.
If the last line of the output does list 22.214.171.124 as the final hop, then your client can communicate with server.