We are in process of upgrade our Windows 2003 Servers. Initially we had 5 Windows 2003 Servers, we migrated 3 of them to Windows Server 2008 R2. We didn't upgrade our DNS and DHCP servers that are running on Windows 2003 Server.
Now we need to migrate our existing DNS and DHCP servers as well. Can anyone guide me step by step. What will be the downtime for clients (if any)? How will it impact network side in our environment?