I am trying to send the results of a query in an email, and each time it takes longer than 5-10 minutes for me to recieve the message. The actual relay from Exchange takes less than one minute, but when I send larger emails (bigger than 200KB), Exchange doesn't even show that it recieved the email.
Wireshark reveals two issues on the client (SQL Server) side:
Database Mail is issuing RSET commands over and over again before sending any data. It takes several minutes before any actual DATA packets are sent.
After Database Mail has sent 14 DATA packets, Exchange immediately acknowledges the packets. Before Database Mail sends the next 14 packets, 10-30 seconds pass with no traffic.
Ultimately, this means that if I am trying to send an email larger than 200KB from SQL Server, I end up with a timeout from exchange after 5 minutes. Has anyone encountered this issue?
I have tried this on multiple machines, and using both SQL 2012 and 2008R2, getting the same results each time.