Outlook Exceptions

The Rules cache wasn't made to be broken. A better way to create e-mail filters will come with Outlook 2003.

Bill: As people in my office start to build junk e-mail filters, they worry about vendors who might get knocked down. So, users have a tendency to add every known e-mail to their exception list.

Many are now getting some message that their e-mail is running out of space. I am sure it is because of an Outlook limitation but can you tell me what the largest number of addresses can be in the exception list? I've searched Technet but have been unable to find the answer.

I would almost like to build a server side list of all of our known contacts and any e-mail not on the list gets knocked down. I'm assuming that would be too large.
— John Eldred


John, Outlook has a 32K limit on the size of the Rules cache. This is an architectural limitation and cannot be overridden with a Registry hack. Outlook 2003, now in beta, has the same limit, but the spam-handling features are a bit more sophisticated so you might be able to tune your spam blocking to stay under the limit.

Get Help from Bill

Got a Windows or Exchange question or need troubleshooting help? Or maybe you want a better explanation than provided in the manuals? Describe your dilemma in an e-mail to Bill at mailto:[email protected]; the best questions get answered in this column.

When you send your questions, please include your full first and last name, location, certifications (if any) with your message. (If you prefer to remain anonymous, specify this in your message but submit the requested information for verification purposes.)

As for doing all this work on the server side, I have good news for you if you're willing to upgrade. Exchange 2003 has lots of great anti-spam features, including the ability to build server-side filters. The filters can block incoming messages from open relays and known spam addresses by downloading lists from a Real-time Blacklist (RBL) vendor. You can also configure the list to exclude or include e-mails based on SMTP domain or sender's IP address.

Hope this helps.

About the Author

Contributing Editor Bill Boswell, MCSE, is the principal of Bill Boswell Consulting, Inc. He's the author of Inside Windows Server 2003 and Learning Exchange Server 2003 both from Addison Wesley. Bill is also Redmond magazine's "Windows Insider" columnist and a speaker at MCP Magazine's TechMentor Conferences.

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