Like Exchange Server 2010 Exchange 2013 offers a built-in Anti-Spam functionality that can filter spam.
The only different is that Microsoft this time created a few anti-spam versions to different servers, for example you can enable a specific Anti-Spam agents for CAS server, Mailbox Server or use all role Anti-Spam agent that is similar to the Exchange Server 2010 anti-spam agent
In this article I’ll show you how to enable the all role Anti-Spam agent since I run both Mailbox and CAS role on my Exchange Server.
To enable Anti-Spam open the EMS and type the following cmdlet from the Exchange installation path which is: %ExchangeInstallPath%Scripts
After you run the script you will see this
Restart the MSExchangeTransport using the cmdlet restart-service MSExchangeTransport
To manage the Anti-Spam please visit the Exchange Server 2013 Anti-Spam cmdlet list