I am running Windows 2000 Small Business Server SP4 with Exchange Server 2000 (says Ver 6.0 SP3). This server also hosts our website using IIS/ISA and our email and is the local proxy and domain controller for our small network.
I am chasing two Spam issues. This one is incoming spam addressed to unresolved recipients in our domain. Currently we are processing about 1000 of these messages an hour 24/7, each one resulting in an NDR that usually fails (fake return address) and goes to the retry queue, and ultimately ends up in the bad mail folder.
So far I have only done research, and set up a twice daily scheduled task to delete the tens of thousands of files from the bad mail folder. I am preparing to install Symantec Mail Security in hopes that using RBLs will cut down what traffic is accepted by the SMTP server. We also run I Hate Spam and I plan to look into anything that software might do to help.
On MS TechNet I found the article "How to forward mail with unresolved recipients to a single mailbox" ( http://support.microsoft.com/?id=315631
). Although I would have to hire a VB programmer to compile the Event Sink, this looks like one possible solution, the trade of being that legitimate misdirected mail would never get an NDR.
Another solution is to contract with an email forwarding service and let them deal with the load, the downside here being cost for which I have no budget.
My question is: What is the Best Practice for dealing with Unresolved Recipients with MS Exchange?