Our company will be split into 2 separate forest. We use Exchange Server 2003 & currently all users have an email address of @ABC.com and @XYZ.com. My question is this: Once the migration is complete, is there a way on the SERVER to create an Auto Reply emailONLY for SPECIFIC email addresses ending in @XYZ.com? I'd prefer no user intervention and I'm open to the messages being undelivered and simply dropped. I'd still like to review an NDR. I'd like to have this accomplished on both internal & internet emails that arrive. Would I need to involve our Mail gateway provider in this equation to assist with the NDR/Auto reply??? Please provide any step-by-step instructions. I've already reviewed the following articles: http://support.microsoft.com/?id=291956, but this doesn't tell me if it's possible for a specific email address user.

Per my knowledge, it cannot be accomplished on the exchange 2003 natively. You may write one custom event sink for it or search for 3rd-party tools For developing event sink please use the Development Forum which would be the most relevant forum for seeking the solution You can also program own event sink, read Event Sinks in the Exchange SDK documentation for basics of it, and then this article provides an overview of how to write event sinks for SMTP and Transport events Other resources: Developing Managed Event Sinks/Hooks for Exchange Server Store using C# Useful Exchange Developer Website