Applies to: Exchange Server 2010 SP3, Exchange Server 2010 SP2

Topic Last Modified: 2011-03-19

Sender reputation is anti-spam functionality that can be used to block messages according to many characteristics of the sender. Sender reputation continuously monitors senders and their past SMTP interactions, such as the amount of spam and messages that aren't spam that a sender has sent. Sender reputation relies on such data about the sender to determine what action, if any, to take on an inbound message.

This topic explains how to use the EMC or the Shell to configure sender reputation.

Note:
Sender reputation is part of the suite of anti-spam features in Exchange. The anti-spam features are only available on Edge Transport servers by default. You can enable anti-spam features on a Hub Transport server even though it isn't recommended. To learn more about enabling anti-spam features on a Hub Transport server, see Enable Anti-Spam Functionality on a Hub Transport Server. The procedures listed in this topic are for configuring anti-spam functionality on an Edge Transport server, but the process is identical on Hub Transport servers.

What Do You Want to Do?

Use the EMC to configure sender reputation

You need to be assigned permissions before you can perform this procedure. To see what permissions you need, see the "Anti-spam features" entry in the Transport Permissions topic.

  1. In the console tree, click Edge Transport.

  2. In the result pane, click the Edge server you want to configure and then select the Anti-spam tab in the work pane.

  3. Right-click Sender Reputation and then select Properties.

  4. The General tab displays the following information about the Sender Reputation feature.

    • Status   Shows whether the Sender Reputation feature is enabled or disabled.

    • Modified   Shows the date and time when sender reputation properties were last modified.

    • Description   Provides a brief description of the Sender Reputation feature.

  5. Use the Sender Reputation tab to enable or disable detection of open proxy servers. A test for open proxy servers is one of the characteristics that sender reputation evaluates to calculate the sender reputation level (SRL). The SRL is a number between 0 and 9 that predicts the probability that a sender is a spammer or an otherwise malicious user. When it's enabled, sender reputation filters all external messages that come through all Receive connectors on that computer. If sender reputation verifies that the proxy server is an open proxy server, it adjusts the SRL rating appropriately. By default, detection of open proxy servers is enabled.

    • Perform an open proxy test when determining sender reputation level To disable detection of open proxy servers, clear this check box. To enable the detection of open proxy servers, select the check box.

  6. Use the Action tab to set the threshold for sender blocking based on SRL. The SRL block threshold defines the SRL value that must be exceeded for sender reputation to block a sender. By default, the SRL value is set at 7. Before you adjust the SRL value, you should monitor its effectiveness at the default level.

    • Sender Reputation Level Block Threshold   Drag the slider to set the SRL block threshold.

    • Threshold Action   Type or select the number of hours that the sender is put on the IP Block list if the SRL block threshold is exceeded. The value must be between 0 to 48 hours.

Use the Shell to configure sender reputation

You need to be assigned permissions before you can perform this procedure. To see what permissions you need, see the "Anti-spam features" entry in the Transport Permissions topic.

You use the Set-SenderReputationConfig cmdlet to configure sender reputation options for your organization.

The following example configures sender reputation to perform an open proxy test for determining sender confidence:

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Set-SenderReputationConfig -OpenProxyDetectionEnabled $true

The following example configures sender reputation to add the IP addresses of hosts that fail the open proxy test to the IP Block List. When you use this parameter, you must also set the OpenProxyDetectionEnabled parameter to $true:

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Set-SenderReputationConfig -SenderBlockingEnabled $true -OpenProxyDetectionEnabled $true

The following example sets the SRL block threshold to 6 and configures sender reputation to add offending senders to the IP Block List for 36 hours:

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Set-SenderReputationConfig -SrlBlockThreshold 6 -SenderBlockingPeriod 36

For detailed syntax and parameter information, see Set-SenderReputationConfig.