I am a new network admin for a company.  I was informed by one of my users that they received over 600 emails this morning.  MOST of which were Undeliverable and after futher research were spam.  I then went back over the previous 2 days when my offices were closed and no emails SHOULD have been sent and there were over 1000...I only know this as it is Small business server tracker's limit.  I went into the exhange servers properties and under security and attempted to remove the Anonymous login.  It would not allow me to remove it, the error said it was inheriting permisions from a parent process.  I know that denie over rides allow permissions.  So I have denied full control.  This SHOULD hopefully close up the whole.  My question is how do I find where it is inheriting permissions to delete it (I looked through group policy and active directory and can't find it).  ALSO, is there a way to allow Anonymous login from within my domain?

Your Exchange server cannot be used as a spam relay if you followed all wizards when you setup that server. Run the CEICW and make sure you make the correct choices. You may want to run some tests to see if your server is OK:

 

Mail relay testing:
http://www.abuse.net/relay.html