Hi All,

We are in the process of migrating Windows 2003 R2 to Windows 2008 R2 systems for our client. Included in the migration are AD, DNS, DHCP, DFS.

I see an issue with the DHCP migration which i did not realize until post validation of the migration.

Issue:

After migrating to new DHCP service the clients get "DNS Servers" as 127.0.0.1 instead of the actual DNS servers which are set in option 006.

Web Browsing and NSLOOKUP to external sites however work fine.

Tests done:

Recreate Scope Options ; Change the DNS update parameters.

Checked the Network Trace using wireshark.. We do see that the ACK does contain the valid IP addresses of the DNS servers. The same new IP addresess are updated in the registry as well under

hklm\currentcontrolset\services\tcpip\parameters\DHCPNameServer.

This setting does not get applied under the IP config settings.

Migration Procedure

Run the command "netsh DHCP server \\<servername> scope x.x.x.x dump>c:\test.txt" - on source server.

Modify the TXT server with new DHCP server details, DNS server details.

Run the command "netsh exec test.txt"- on the target server.

Deactivate Scope and Unauthorize old DHCP server then Activate Scope, Authorize the new server.

On another site, we did some troubleshooting with the Binding, credentials, DNS update, clearing the leases etc and finally it worked. The sad part is that i dont know which setting actually resolved this issue.

Any help would be greatly appreciated as the last thing i would do is remove DCHP and create the scope manually and try.

Hi

 Could please follow the steps on TechNet forums answer for dhcp migration;

https://social.technet.microsoft.com/Forums/en-US/e0985e39-27d7-4a44-954f-d71c81ffa45a/dhcp-200320082012?forum=winserveripamdhcpdns

Also do not any modify on backup.txt file,if needs you could modify necessary settings after the migartion on scopes.

Hi

 Could please follow the steps on TechNet forums answer for dhcp migration;

https://social.technet.microsoft.com/Forums/en-US/e0985e39-27d7-4a44-954f-d71c81ffa45a/dhcp-200320082012?forum=winserveripamdhcpdns

Also do not any modify on backup.txt file,if needs you could modify necessary settings after the migartion on scopes.

Hi Burak,

I will try the steps, but unfortunately the site we migrated was moved into production and i can do this test only during off-business hours. But i will do it some time today and update this post.

and also on migration steps,there won't be any any scope on target server.(if there is,just delete all scopes),

Hi Prashant,

Reboot the DHCP server, and reboot the client. Type ipconfig /release, ipconfig /renew on client and check the result.

When doing nslookup, which DNS server is client using?

Check the events of DHCP server to see if there are any errors.

Best Regards,

Leo