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DNS is showing old records in DHCP broadcast

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Last Modified: 2013-12-02
Hi,

Basically I have an issue with the DHCP that is issued to the users whom I support. When a user turns on the machine each morning, they are getting the DNS address settings of the old domain which the server used to belong to. Its really bizarre because everything else is fine.

I have checked the DHCP from the server in the site and it is completely switched off. We give out DHCP from a central data centre in the US...

If I do an IPCONFIG /RENEW from a command prompt on the machines that are affected - the right settings do come across. If the user reboots their PC/Laptop, the problem then restarts again.

This is affecting their MS Office Communicator which is where the problems are happening.

Any ideas or suggestions would be greatly received.

Many thanks,

Ambrish
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Hypercat (Deb)President
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Commented:
This could be a DNS caching issue on the workstations.  If there's some lag in the connection to the DHCP server, the workstations may be defaulting back to cached information.  After doing the ipconfig /release and /renew, run the following commands:
ipconfig /flushdns
ipconfig /registerdns
Then try a reboot and see if they retain the correct DNS information.

Author

Commented:
Thanks Hypercat, I'll give that a go and update this question thereafter. :)

Author

Commented:
I tried the suggestion you gave Hypercat but unfortunately the DNS records still point to the old server... :(
Is this happening on all machines or just certain ones?

Make sure no alternate DNS servers are specified on the machine. Check in TCP/IP properties > Advanced > DNS.

If that doesn't help I am also curious if your DHCP server addresses changes from the time the DNS server is wrong to when it is right. If you do a ipconfig /all before and after you do ipconfig /renew to fix the DNS server issue does the address of the DHCP server change?

Author

Commented:
Hi Techno-Wiz,

I have checked in Advanced > DNS in the TCP/IP properties... and there is nothing there.

I also tried the second thing, and bizarrely the DHCP stays the same the entire time, the only thing which changes are the DNS records which confuses the heck out of me even more.
Well that would indicate to me that the wrong DNS server is definitely coming from the DHCP server. Is this happening to just one user or many? I would double check the configuration of the DHCP server such as scope options and server options to make sure there are no conflicts.
Commented:
Solution was that the phone systems were giving out the incorrect DNS settings...

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