Client DNS issue after Domain controller migration

Sabir Shibley 41 Reputation points
2020-12-06T09:50:42.11+00:00

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

Active Directory
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A set of directory-based technologies included in Windows Server.
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Windows DHCP
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Windows Server Migration
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Windows Server: A family of Microsoft server operating systems that support enterprise-level management, data storage, applications, and communications.Migration: The process of making existing applications and data work on a different computer or operating system.
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Accepted answer
  1. Thameur-BOURBITA 32,621 Reputation points
    2020-12-06T14:25:20.443+00:00

    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.

    Please don't forget to mark this reply as answer if it help you to fix your issue

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  1. Thameur-BOURBITA 32,621 Reputation points
    2020-12-06T13:13:10.44+00:00

    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:

    45501-image.png

    Please don't forget to mark this reply as answer if it help you to fix your issue

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  2. Dave Patrick 426.5K Reputation points MVP
    2020-12-06T13:23:22.36+00:00

    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.

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  3. Sabir Shibley 41 Reputation points
    2020-12-06T13:31:25.49+00:00

    45458-ptr.jpg
    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

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  4. Thameur-BOURBITA 32,621 Reputation points
    2020-12-06T14:00:34.29+00:00

    Hi,

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

    45329-image.png

    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

    Please don't forget to mark this reply as answer if it help you to fix your issue