Client DNS issue after Domain controller migration

Question

i had migrated from 2008 R2 Domain controller to 2016, all FSMO roles transferred to 2016 server. after migration existing clients machines not resolving new server DNS, it gives below error.

C:\Users\administrator.CLOUD>nslookup
DNS request timed out.
timeout was 2 seconds.
Default Server: UnKnown
Address: 192.168.201.11

new servers are able to resolve 2016 server DNS without any issue.

i did not demoted 2008 R2 domain due to DNS issue. i tried registering DNS manually but no luck

Answer 1

Hi,

it seems a network issue. check if the DNS network flow port 53 used by the client to send DNS request is opened between client and new DNS server. you can use this tools https://www.microsoft.com/en-us/download/details.aspx?id=24009
It can be also a DC problem because the DNS zone is active directory integrated so , it can be impacted if there is a replication issue.

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Answer 2

Hi,

Default Server: UnKnown this message means that there is no PTR entry (it's DNS entry to identify the server name by its IP addresse) for new DNS server. but the PTR dns entry is not required to let client send DNS requests to the server 192.168.201.11 .

check if the client is able to resolve FQDN of any machine to test if it get answer from DNS server 192.168.201:

nslookup domainName:

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Answer 3

Please run;

Dcdiag /v /c /d /e /s:%computername% >c:\dcdiag.log
repadmin /showrepl >C:\repl.txt
ipconfig /all > C:\dc1.txt
ipconfig /all > C:\dc2.txt

then put unzipped text files up on OneDrive and share a link.

Answer 4

Hello Thmeur,
PRT record is fine

C:\Users\administrator.CLOUD>nslookup google.com
DNS request timed out.
timeout was 2 seconds.
Server: UnKnown
Address: 192.168.201.11

DNS request timed out.
timeout was 2 seconds.
DNS request timed out.
timeout was 2 seconds.
DNS request timed out.
timeout was 2 seconds.
DNS request timed out.
timeout was 2 seconds.
*** Request to UnKnown timed-out

if i use my old domain IP it works fine, old domain 201.1 and new 201.11

C:\Users\administrator.CLOUD>nslookup
Default Server: dc.cloud.local
Address: 192.168.201.1

192.168.201.11

Server: dc.cloud.local
Address: 192.168.201.1

Name: ad2016.cloud.local
Address: 192.168.201.11

Answer 5

Hi,

The PTR you shared it in your last answer is for : 192.168.201.3

Create new PTR for 192.168.201.11.

Try to resolve a FQDN with local DNS suffix : nslookup dc.cloud.local to check if you get the same timeout

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