Configure Sender Filtering Properties

Applies to: Exchange Server 2010

The Sender Filter agent is an anti-spam agent that is enabled on Edge Transport servers. You can use the Sender Filter to block incoming messages from specific individual senders or domains.

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

Note

Sender filtering 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 filtering
• Use the Shell to configure sender filtering

Use the EMC to configure sender filtering

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 Filtering and then select Properties.
4. The General tab displays the following information about the sender filtering feature.
   • Status   Shows whether sender filtering is enabled or disabled.
   • Modified   Shows the date and time when sender filtering properties were last modified.
   • Description   Provides a brief description of sender filtering.
5. Use the Blocked Senders tab to specify e-mail addresses or domains from which you want to block messages.
   • Add   To add new addresses and domains to the blocked senders list, click Add. In the dialog that appears, use the following fields to specify a sender:
     ◊ Individual e-mail address   To block an individual sender, select Individual e-mail address and then type the Simple Mail Transfer Protocol (SMTP) address of the sender that you want to block. For example, type kim@contoso.com.
     ◊ Domain   To add all senders from a domain to the blocked senders list, select Domain, and then type the domain name in the domain field, such as contoso.com.
     ◊ Include all subdomains   To include all subdomains to the blocked domain, select Include all subdomains. This check box is active only when you select Domain.
   • Edit   To change a blocked sender's address or domain, click the sender's address, and then click Edit.
   • Remove To delete a blocked sender's address or domain, click the sender's address, and then click .
   • Block messages that don't have sender information   To block messages that don't have sender information, select this check box.
6. Use the Action tab on the sender filtering properties to configure the Sender Filter agent to take one of the following actions when a blocked sender or domain is identified.
   • Reject message   To reject the message and send a "554 5.1.0 Sender Denied" SMTP session error to the sending server, select Reject message. Reject message is the recommended setting.
   • Stamp message with blocked sender and continue processing   To update the metadata of the message to indicate that this message was sent by a blocked sender, select this setting. This stamp is used by the Content Filter agent when it calculates the spam confidence level (SCL) for the message. Additionally, sender reputation uses the SCL for a particular message when it calculates a sender reputation level (SRL) for the sender of the message.

Use the Shell to configure sender filtering

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-SenderFilterConfig cmdlet to manage sender filtering. The following example configures the Sender Filter agent to block messages from the specific e-mail addresses kim@contoso.com and john@contoso.com:

Set-SenderFilterConfig -BlockedSenders kim@contoso.com,john@contoso.com

The following example configures the Sender Filter agent to block messages from the specific domain fabrikam.com:

Set-SenderFilterConfig -BlockedDomains fabrikam.com

The following example configures the Sender Filter agent to block messages from the specific domain northwindtraders.com and all its subdomains:

Set-SenderFilterConfig -BlockedDomainsAndSubdomains northwindtraders.com

The values that you specify by using the parameters shown in the examples above replace the existing list of blocked senders. To preserve the existing list, you could specify the existing senders along with any new senders you want to add. However, this can be a cumbersome task especially if you have many SMTP addresses or domains from which you block incoming messages. Instead, you can use a temporary Shell variable to add an address or domain to the blocked senders list. The following example uses the temporary variable $Configuration to add the sender john@contoso.com and the domain tailspintoys.com to the blocked senders list:

$Configuration = Get-SenderFilterConfig
$Configuration.BlockedSenders += "john@contoso.com"
$Configuration.BlockedDomains += "tailspintoys.com"
Set-SenderFilterConfig -BlockedSenders $Configuration.BlockedSenders -BlockedDomains $Configuration.BlockedDomains

The following example shows how to configure the Sender Filter agent to block messages that don't specify a sender in the MAIL FROM: SMTP command:

Set-SenderFilterConfig -BlankSenderBlockingEnabled $true

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