the sender <> is normal exchange NDR’s being delivered. Since your exchange server is authoritative for you domain any messages addressed to non existent email address will cause these, since a lot of spam has bogus address you tend to see them sitting in your ques for a while. They will eventually time out and go away on their own.
Nothing to worry about. From: Steve Ens Sent: Tuesday, April 08, 2014 4:30 PM To: [email protected] Subject: [Exchange] Relaying I'm running exchange 2010 here with all the service packs. I think that I must have misconfigured one of my receive connectors. I know I am not an open relay from the outside, but I think I have a machine inside my network that is compromised and using exchange to send out since I have many messages sitting in my queue that are undeliverable. Any suggestions as to how I'd determine from which IP these messages are originating? The sender always looks like <> I've opened up the message tracking logs, but can't find any incriminating evidence there.
