I'm curious, all - if there's a 15-45 second delay between the time you type "Enter . Enter" and the time you see the "Queued for Delivery" response in an SMTP conversation, and it only occurs when the RCPT TO: line has an external to your Exchange 2013 email address, what is causing the delay?
If the RCPT TO: line has an accepted domain address, the "Queued for Delivery" response is immediate. I'm pretty sure the telnet session is passing thru an F5, but I do see an Exchange SMTP banner at the start of the telnet session. Any ideas? I'm tempted to say DNS/AD lookups, but then again, I'd expect that to be after the SMTP session was done. Thanks! Russ
