Message Filtering Limits

If you use the message filtering feature of Exchange 2000, you'll know that you can block certain addresses from sending messages into your system. Ideally, you'll be using 3rd party software to control senders and recipients, but if you are using message filtering, be aware of one limitation of the feature.

There is a limit to the number of addresses that you can add to the filter list. The number is around the 850 mark and if you reach this limit, you'll receive an error message similar to the following:

"The administrative limit for this request was exceeded"

Note that is limit is by design, and is actually an Active Directory limit. The technical details behind this restriction were highlighted by a Microsoft source, who said that there is a limit to the number of non-linked attributes that can be stored in the Active Directory. This has to do with the fact that a nine-byte tag must be put on the record for that database object and database records cannot span multiple database pages which are limited to a size of 8k per page. That implies a theoretical upper limit of 910 values across all non-linked attributes on a single DS object. However, the number is actually lower by approximately 50 because of fixed fields in the database record. Currently, there is no method to increase the total number of the entries.

So now you know. If you hit that limit, you can blind your boss with science.

Account Deleted on September 29, 2003 at 05:02 AM in Useful Info
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Good morning,

We are in the middle of migrating users from MS Exchange 5.5 to E2K. We have accidentally created over 2800+ duplicate users in AD/Exchange Address book. If we delete one of the bogus entries, it deletes all the entries through the domain. The MS Exchange ver. 5.5 is running on NT boxes and the E2K version is running on MS 2000 server boxes. Has anyone seen this and what is anything did you do to fix it?


Posted by: Michael at Dec 1, 2003 10:58:57 AM

Have you tried using the AD cleanup wizard?;en-us;270652

Posted by: Chris Meirick at Dec 1, 2003 2:16:25 PM