DHCP clients

I had 2 DC's in my domain, each DC also ran a DHCP server. We split the scope x.x.x.50-100 on DCA and x.x.x.100-200 on DCB. We did this for 5 different VLANs

When clients connected they would go to DCA first then if all DHCP Ip's were used for their VLAN they would go to DCB.

Recently we've replaced DCA with a new windows 2012 R2 server as our DC. We migrated DHCP from DCA to our new Win 12 DC. Problem is that clients are refusing to go to the new DC to get DCHP. They keep going to DCB. I've confirmed that the migrated scope is activated and authorized
iamuserAsked:
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JohnBusiness Consultant (Owner)Commented:
On a problem computer, try resetting TCP/IP

Open cmd.exe with Run as Administrator
Then  netsh int ip reset c:\resetlog.txt
Also, ipconfig /flushdns followed by net stop dnscache followed by net start dnscache
Then restart the computer

See if that works and please let us know.
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Will SzymkowskiSenior Solution ArchitectCommented:
We did this for 5 different VLANs

 When clients connected they would go to DCA first then if all DHCP Ip's were used for their VLAN they would go to DCB.

 Recently we've replaced DCA with a new windows 2012 R2 server as our DC. We migrated DHCP from DCA to our new Win 12 DC. Problem is that clients are refusing to go to the new DC to get DCHP. They keep going to DCB. I've confirmed that the migrated scope is activated and authorized

Based on the above the reasons why they would be refusing to go to DCA are below...
- DHCP server is not Authorized (not likely)
- You are using a different IP for the new 2012DC server, if this is the case then you probably forgot to add the IP Helper Address for the new server IP, for all of your VLAN's. This is required for clients to communicate to the DHCP server over different VLAN's. If this is not in place it will not reach the DHCP server. (more likely the issue).

If neither of these are the case then i would check your firewall as well on this machine and also the event logs.

Will.
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iamuserAuthor Commented:
Sorry for late response but IP Helper was the issue. I totally forgot about that
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