On Thu, Sep 30, 2010, Victor Duchovni wrote: > Do you have a tcpdump capture? From the above it sounds like HELO is > sent before the 220 banner. That's a protocol error.
Is it? 4.3.1 Sequencing Overview ... One important reply is the connection greeting. Normally, a receiver will send a 220 "Service ready" reply when the connection is completed. The sender SHOULD wait for this greeting message before sending any commands. So this is "just" a SHOULD, not a MUST, hence not a protocol error per se. Any real MTA will obey the SHOULD requirement of course.
