FQDN names resolved with duplicated DNS suffix
Posted on 2017-06-19
I have a quick question I hope you can help me to fix.
Environment: I have an environment where I have installed a new AD and the domain name is something like corp.example.com
As a NETBIOS name during the AD install wizard I did choose "example" to make things easier and consistent with the public DNS name. The public DNS registered is example.com and there is public website running with example.com already hosted by WordPress and DNS registrar is GoDayddy.
Issue: Internal host names are not resolved properly with NSLOOKUP
1. Hostnames are working fine
2. IP Addresses are working fine
3. FQDN are NOT working fine. They are resolved with internal domain appended to external domain name.
eg. "VM1.CORP.EXAMPLE.COM" returns VM1.CORP.EXAMPLE.COM.EXAMPLE.COM and public IP Address registered with the website DNS Provider
4. FQDN with a trailing "." are working fine
eg. "VM1.CORP.EXAMPLE.COM." returns the correct IP Address as expected
Configuration: AD/DNS server is pointing at itself. NO forwarders configured. AD is pointing at an internal Gateway. This gateway is configured to talk with the internet using a different network through a separate Router connected to the internet.
My question: It's obviously not a question of routing but I dont understand why DNS forwards queries for FQDN names to external DNS servers considering that "A" and respective "PTR" records are fully registered and working on the builtin DNS? Of course this is affecting ANY operation you can think of from joining machines to domain to leverage network services through FQDN names! What am I missing here?
Any help is greatly appreciated!