Enable anti-spam functionality on Mailbox servers


Applies to: Exchange Server 2013

Topic Last Modified: 2014-01-23

In Microsoft Exchange Server 2013, the following anti-spam agents are available in the Transport service on Mailbox servers, but they are not installed by default:

  • Content Filter agent

  • Sender ID agent

  • Sender Filter agent

  • Protocol Analysis agent for sender reputation

However, you can install these anti-spam agents on a Mailbox server using a script in the Exchange Management Shell. Typically, you would install the anti-spam agents on a Mailbox server only when your organization accepts all incoming mail without any prior anti-spam filtering.

Although the Recipient Filter agent is available on Mailbox servers, you shouldn't configure it. When recipient filtering on a Mailbox server detects one invalid or blocked recipient in a message that contains other valid recipients, the message is rejected. Although the Recipient Filter agent is enabled by default, it isn't configured to block any recipients. For more information, see Manage recipient filtering on Edge Transport servers.

What happens if you install the available anti-spam agents in the Transport service on a Mailbox server, but you also have other Exchange anti-spam agents operating on the messages before they reach the Mailbox server? For example, what if you have an Edge Transport server in the perimeter network? The anti-spam agents on the Mailbox server recognize the anti-spam X-header values that are added to messages by other Exchange anti-spam agents, and messages that contain these X-headers pass through without being scanned again. However, recipient look-ups performed by the Recipient Filter agent will occur again on the Mailbox server.

  • Estimated time to complete this task: 15 minutes

  • You need to be assigned permissions before you can perform this procedure or procedures. To see what permissions you need, see the "Transport configuration" entry in the Mail flow permissions topic.

  • The Connection Filter agent and the Attachment Filter agent aren't available on Mailbox servers. They're only available on an Edge Transport server. However, the Malware agent is installed and enabled by default on a Mailbox server. For more information, see Anti-malware protection.

  • For information about keyboard shortcuts that may apply to the procedures in this topic, see Keyboard shortcuts in the Exchange admin center.

Having problems? Ask for help in the Exchange forums. Visit the forums at Exchange Server, Exchange Online, or Exchange Online Protection.

Run the following command:

& $env:ExchangeInstallPath\Scripts\Install-AntiSpamAgents.ps1

You know this step worked if the script runs without errors, and asks you to restart the Microsoft Exchange Transport service.

Run the following command:

Restart-Service MSExchangeTransport

You know this step worked if the Microsoft Exchange Transport service restarts without errors.

You need to specify the IP addresses of any internal SMTP servers that should be ignored by the Sender ID agent. In fact, you need to specify the IP address of at least one internal SMTP server. If the Mailbox server where you're running the anti-spam agents is the only SMTP server in your organization, specify the IP address of that computer.

To add the IP addresses of internal SMTP servers without affecting any existing values, run the following command:

Set-TransportConfig -InternalSMTPServers @{Add="<ip address1>","<ip address2>"...}

This example adds the internal SMTP server addresses and to the transport configuration of your organization.

Set-TransportConfig -InternalSMTPServers @{Add="",""}

To verify that you have successfully specified the IP address of at least one internal SMTP server, do the following:

  1. Run the following command:

    Get-TransportConfig | Format-List InternalSMTPServers
  2. Verify the IP address of at least one valid internal SMTP server is displayed.