Block Threshold

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Block Threshold

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The Block Threshold is an attribute applied to the entire organization against which the spam confidence level (SCL) of a given message is compared. If the SCL level of the message is above the Block Threshold, the content filter should apply a custom action to the message. If the SCL of a message is at or below the Block Threshold, the SCL rating is added as a message property, and the entire message is transmitted to the Exchange store for delivery. The Block Threshold would typically be set as a high bar to block easily detectable spam while yielding few false positives.

The Block Threshold can be set in Microsoft® Active Directory® in the ms-Exch-Uce-Block-Threshold Attribute or in a registry key or configuration file.

The following should be considered when setting the Block Threshold in Active Directory:

  • Provides a central repository.
  • Updates are applied across the entire organization.
  • The filter must issue LDAP queries.
  • The filter must poll Active Directory to determine if the threshold has been modified.
  • The filter must handle domain controller/global catalog configuration.

The following should be considered when setting the Block Threshold locally per server:

  • Straightforward local access (on computer).
  • No dependency on Active Directory (hence, no LDAP queries, no need to poll Active Directory, no need to handle domain controller/global catalog configuration).
  • To modify the threshold, each server must be updated.

For an example of how to set this attribute on the UCE Content Filter object in Active Directory, see Creating the Content Filter Object.

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This topic last updated: September 2003

Build: June 2007 (2007.618.1)

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