Just a quick run down. Just deployed a new Exchange 2013 SP1 no CU just straight SP1 on Server 2012 R2. There is only 1 server here so the exchange is also on the Active Directory. We also have only 1 name on our certificate which is remote.ourdomain.com.
-Also note we have a spam filter in the cloud before it reaches our exchange server and I don't have any spam filtering turned on, on the server itself.
-MXToolbox says we are not an open relay.
On to the problem. I know straight out of the box exchange 2013 is not configured ideally. I noticed when i went to the exchange toolbox and checked the queue viewer i saw a bunch of messages from address "<>". So I cleared out a bunch of them and they seem to slowly come back over time.
The Receive Connectors I did not touch they are default from the server install.
The Send Connectors I created 1 entry on the..
*delivery it is using "MX record associated with recipient domain"
*scoping under address space i have 1 entry "type=SMTP FQDN=* cost=1" under source server our only server is selected and at the bottom is FQDN which I have left blank.
I've tried many google searches and not found much information regarding this except for older exchange servers, which seemed easier to setup.