Question : Receive connector Permission Groups

1.)I am creating a receive connector to receive emails from our Mail marshall server which is on domain as well.Created a custom receive connector in the permissions group should I tick the anonymouse users or any thing else.Can any one else explain me what each one is used for.

2.)Also on exchange 2010 server I want to reject receiving internal emails for a particular group of users.I have used the below article but want to know is their a better way to restrict users from receiving  internet emails.

Answer : Receive connector Permission Groups

those permissions are the supported authentication types on the receive connector, I think for mail marshal you might configure anonymous refer to their manual
http://technet.microsoft.com/en-us/library/aa996395.aspx

for the second question you didn't mention the link but did you use transport rules!