SBS 2008: Unable to manage DHCP when an invalid name record exists in hosts file

Under certain circumstances, you might be unable to manage DHCP and get a error screen. This could be the result of having a record for the servers IP address in your hosts file which resolves to a name that does not exist in Active Directory. Since DHCP does a reverse lookup on the binding IP […]

Under certain circumstances, you might be unable to manage DHCP and get a error screen. This could be the result of having a record for the servers IP address in your hosts file which resolves to a name that does not exist in Active Directory. Since DHCP does a reverse lookup on the binding IP (your internal server’s IP) to discover the computer object in AD to authorize it for DHCP services, a return of an invalid hostname’ll cause the authorization to fail. You can verify this as well by performing a ping test as follows to verify the bad resolution of the servers IP to its name. On this example, we will assume that the server’s internal IP is 192.168.16.2 and the server name’s SERVER.CONTOSO.LOCAL. C:\Windows\System32\drivers\etc>ping -a 192.168.16.2
Pinging badhosts.record.com [192.168.16.2] with 32 bytes of data: As you can see from the output, the reverse name resolution for the server’s IP does not match the server’s name and thus won’t match the AD object.
Resolution: To resolve this simply delete the record out of your hosts file which is found in %windir%\system32\drivers\etc.