When you host your DNS zone from your internal DNS servers inside your network, you tend to get some results that display incorrectly when there is an external DNS change. The public zone for your DNS may actually be hosted in a different location than internally on your network. So if this is part of your case, then here are some steps you can use to resolve some of the most common issues with internal and external hosting of your public DNS zone.
In this scenario, The public web server ip address was changed. (Not uncommon)
The way to identify and resolve is by going to a public DNS server and resolving the name.
In this case,
Internal DNS services provided by your internal DNS servers are resolving your public web servers with the old IP Address. This requires an update to the new IP address.
EXTRA ISSUE, your internet provider doesn't allow public DNS resolution. They insist that you use their DNS only. So your internal DNS troubleshooting is limited to their servers.
1. Using an external device (OFF NETWORK), go to the command prompt do NSLookup, and type in the Fully Qualified Domain Name (FQDN) of your website. (
www.<yourwebsite>.com You will get the public address for the new webserver.
2. Note and add this address to the local DNS server inside your network.
3. Once that is completed, you will need to refresh/reload the internal zone from within the DNS Manager. At your workstation command prompt type ipconfig /flushdns to clear any current entries on the workstation. Once you get the new address, open a browser to check connectivity. You may have to do the NSLOOKUP a couple of times to get the new address.
Hope this is helpful.
That's all folks.