By default hub transport servers have anti-spam features disabled. In certain situations, for example in small organizations where you don’t plan to use edge transport servers, you would want to enable this functionality. To do so, follow these steps:

1. Open up Exchange Management Shell
2. Position to %system drive%/Program Files\Microsoft\Exchange Server\V14\Scripts folder and run the following commands:

./install-AntispamAgents.ps1
Restart-Service MSExchangeTransport

3. As final step, to make all anti-spam features work correctly, Exchange needs to know about your SMTP servers so you need to run (šut your own IP addresses here, you can also write address ranges like 192.168.1.0/24):

Set-TransportConfig -InternalSMTPServers 192.168.1.10,192.168.1.11

Last step can also be done through Exchange Management Console. Anti-spam features should now be also visible in it. To further manage anti-spam features refer to Technet.