Warning about internal SMTP Servers

I am using Exchange Server 2010 with Forefront Protection 2010 for Exchange on Windows Server 2008 R2. I am getting this warning in the event log:

Event 1022, MSExchangeTransport, SmtpReceive

Anti-spam agents are enabled, but the list of internal SMTP servers is empty. If there are any MTAs between this server and the Internet, populate this list by using the Set-TransportConfig cmdlet in the Exchange Management Shell.

I do not have any MTAs between this stand alone server, which is on the internet. How do I get rid of these warnings, or are they important?