RODC is the new feature introduced from the windows 2008 means domain controller with read only partitions which includes AD database and Sysvol/Netlogon folder.In order to introduce RODC in existing windows 2003 environment you need to prepare your existing environment Adprep /Rodcprep (Adprep32or is dependents on OS means Adprep32required to be executed on 32bit OS and on 64 bit OS).RODC can’t provide substitute for a DC when WAN link is down and the reason is RODC can’t issue Kerberos ticket to the domain clients.
The local clients should use the RODC for their DNS queries. Hot Scripts offers tens of thousands of scripts you can use. d Bforums offers community insight on everything from ASP to Oracle, and get the latest news from Data Center Knowledge.In the event the client needs to write a record, such as during a DHCP lease, the client will be redirected to a writable DNS server for the write operation. I’m not big fan of RODC, reason is RODC alone doesn’t work like a domain controller but for each and everything it relies on RWDC(Writable domain controller) causing heavy replication traffic.The replication happens in RODC is unidirectional means changes made on RODC is not replicated to RWDC, but you can still connect to RWDC console from RODC and make modification on RWDC which is still vulnerable.However, an RODC only has read-only copies of DNS information and there's no way to replicate DNS changes to writable DNS servers. When a client makes a write request, they first make a request for an authoritative server to their configured DNS server, which would be the RODC in this scenario.
The RODC will try to find a writable DNS server in the client's local site and send the client a name server resource record for the writable DNS server so the client can make the update.Read-Only Domain Controllers Step-by-Step Guide has nice writeup on RODC integration with DNS . Domain Controller Planning and Deployment Guide 2008 RODC Tick List for Deployment for Deploying an RODC Domain Controller (RODC) Branch Office Guide displaylang=en&id=3608 RODC Post-Installation Configuration RODCs in the Perimeter Network RODCs in the Perimeter Network DS/RODC in the Perimeter Network (Windows Server 2008) Adprep /rodcprep should be executed on the DC holding Domain Naming Master FSMO role not on any DC.It is not mandatory to run Adprep /rodcprep in existing windows 2000 or 2003 AD environment until you plan to deploy RODC may be now or in future.RODC hold the read only database means the location where RODC is deployed you can’t make any changes and changes made on the RODC is not replicated to any other DC since replication is unidirectional from RWDC to RODC only not vice versa.