Customer is having issues talking to active directory and ran a dns test with the results
INFO: exploring forest using domain controller: server1.company.com
>>>>>: (DNS) - testing domain: COMPANY
INFO: according to DNS, the following services are available:
INFO: (PDC) - server2.company.com = 10.90.7.7
INFO: (GC) - server2.company.com = 10.90.7.7
INFO: (GC) - server2.company.com = 10.90.7.7
INFO: (GC) - server1.company.com = 10.90.7.8
INFO: (DC) - server2.company.com = 10.90.7.7
INFO: (DC) - server2.company.com = 10.90.7.7
INFO: (DC) - server1.company.com = 10.90.7.8
INFO: (LDAP) - server2.company.com = 10.90.7.7
INFO: (LDAP) - server1.company.com = 10.90.7.8
INFO: (LDAP) - server2.company.com = 10.90.7.7
INFO: (DNS) - name resolution for domain: COMPANY
INFO: (DNS) - 10.90.7.7 -> ERROR: missing PTR record (reverse DNS).
INFO: (DNS) - 10.90.7.8 -> ERROR: missing PTR record (reverse DNS).
INFO: (DNS) - SRV record: priority:0 weight:0 port:389 host:server2.company.com
INFO: (DNS) - name resolution for: server2.company.com
ERROR: (DNS) - missing PTR record (reverse DNS) for domain controller: 10.90.7.7
INFO: (DNS) - SRV record: priority:0 weight:100 port:389 host:server2.company.com
INFO: (DNS) - name resolution for: server2.company.com
ERROR: (DNS) - missing PTR record (reverse DNS) for domain controller: 10.90.7.7
INFO: (DNS) - SRV record: priority:0 weight:100 port:389 host:server1.company.com
INFO: (DNS) - name resolution for: server1.company.com
ERROR: (DNS) - missing PTR record (reverse DNS) for domain controller: 10.90.7.8
<<<<<: (DNS) - testing domain: COMPANY
>>>>>: (DNS) - testing domain: StudentLab.company.com
INFO: according to DNS, the following services are available:
<<<<<: (DNS) - testing domain: StudentLab.company.com
Any Error: lines in there need to be fixed in your Microsoft AD dns server. Many times there is left over information from old servers, servers that have been renamed or re purposed. Some times there is old information from a server that was installed but was incorrectly configured. When the server is fixed, the new information gets registered but the old information is not removed.
Also use the Microsoft dnslint program to validate your MS AD DNS information. All errors should be resolved to ensure proper dns resolution.