| > Why the protocol error ? This implies the sender issued "DATA" even
| > though all the (one) recipients had been rejected.
|
| It's to do with pipelining - an optimisation thing. The box sending the
| mail sends:
|
| packet 1: EHLO ....
|
| packet 2: MAIL FROM:<foobar@???>
| RCPT TO:<you@???>
| DATA
|
| packet 3..n: the actual data
|
| So, instead of 5+ small packets, we manage to remove two packets from
| every pipelined SMTP transaction.
Ahh - I understand now - thanks.
I'd recently enabled log_selector = +smtp_protocol_error (off by default)
which explains why I'd not noticed this before.
| I question why exim complains about a protocol violation given that
| this is a legal and allowed optimisation. Sure it would be a protocol
| violation if someone sent only MAIL FROM and DATA commands with no
| RCPT TO.
Hmmm
Details aside, it seems wierd for exim->exim dialogs to include protocol
errors...
