I have recently deployed exchange server 2013, and I am new to this. I am facing issue in securing exchange server.
Details: My Active directory and exchange server are remote on public IP and can be accessed VIA internet
I want only authenticated users from my domains to be able to send emails. so in Mail Flow --> receive Connectors --> Default Frontend --> Security --> I unchecked the "Anonymous users"
No problem so far, and authenticated users are able to send emails, but when i tried to send an email from my gmail account to my exchange server user i Error "530 5.7.1 Client was not authenticated"
So now situation is, If i allow "Anonymous users" for my "Receive Connectors --> “Default Frontend” I am able to receive emails from external domains like gmail etc. But that allows unauthenticated users to send emails.
On the other hand if i disable "Anonymous users", i am unable to receive emails from internet.
I tried creating a new receive connector for "Internet (For example, to receive internet mail)"
But it gives me error that port and ip bindings must be unique.
I am lost. can some one please advise what i need.