Many IT administrators, when faced with the task of troubleshooting DNS name resolution issues, find that their DNS queries only work for the fully qualified domain name (FQDN) and not the short name. The FQDN is the full name of a computer, including both the local hostname and the domain name. The short name, on the other hand, is just the local hostname without the domain name.
The most common cause of this issue is a misconfigured DNS server. When a DNS server is set up, it needs to be configured with the proper settings for the domain it is servicing. If the DNS server is not configured properly, then it will not be able to resolve short names.
The first step in resolving this issue is to check the DNS server. Make sure that the name server is configured with the proper settings for the domain in question. Once the DNS server is configured correctly, the next step is to make sure that the DNS client is configured correctly. The DNS client needs to be configured with the proper IP address of the DNS server in order for it to be able to resolve names.
If the DNS server and the DNS client are configured correctly, then the next step is to check the DNS cache. The DNS cache is a temporary storage of the most recently resolved DNS queries. If the DNS cache contains an incorrect entry, this can cause the DNS query to fail even if the DNS server is configured correctly. To flush the DNS cache, you can use the ipconfig /flushdns command on Windows or the dscacheutil -flushcache command on Mac OS X.
If the DNS cache is not the issue, then the next step is to check the network configuration. Make sure that the network is configured properly and that the DNS traffic is being routed correctly. If the DNS traffic is not being routed correctly, then the DNS queries will not be successful.
If all of the above steps have been taken and the issue still persists, then the final step is to check the hosts file. The hosts file is a local file that contains DNS mappings. If the hosts file contains an incorrect entry, then this can cause the DNS query to fail even if the DNS server and client are configured correctly. To check the hosts file, look for an entry that contains the FQDN and make sure that the entry is correct.
In conclusion, if your DNS query only works for the fully qualified domain name and not the short name, then the most likely culprit is a misconfiguration of either the DNS server or the DNS client. Make sure that both the DNS server and the DNS client are configured correctly, and if they are, then check the DNS cache and the network configuration to make sure that the DNS traffic is being routed correctly. If all else fails, then check the hosts file to make sure that the entry for the FQDN is correct.