We have a file server running windows server 2008 standard with AD on it, this is a domain controller. We have another windows 2008 server running terminal services and is not a domain controller. We have another server running windows 2003 server on it and it is not being used for anything nor is it a domain controller. We would like to have either the terminal server or the 2003 server to have a backup of AD on it that could be used if the file server went down. Can anyone give us a hand on how this would be accomplished so that replication of AD would take place and would the terminal server or the 2003 server be the best choice.