Re: Multi-line Greetings - where to put official greeting line (Top or Bottom?)

[ned+ietf-smtp@xxxxxxxxxxx]

> I did however discover one thing. I was sending the initial greeting
> via 2 write sys-calls. Think of it like this:

> write(fd, "220 h.db.org ESMTP ready", 24);
> ...
> ...
> write(fd, "\r\n", 2);

> This confused the "Mail Test" to the point where it claimed not to
> have received a valid response. Now I'm no expert, but I can't remember
> having read anything that mandates that the whole response be sent in
> one TCP packet.

That's because there is no such mandate. And even if there were such a mandate
it could not be enforced from an application since how a TCP stack decides to
map I/O operations into packets on the wire can and does vary. (Some
implementations allow some degree of control over this but others do not.)

> With the exception of spam sending malware it doesn't
> seem to be a problem for anyone else sending me mail.

Right, because implementations are supposed to be tolerant in this regard.

> Can someone confirm that it is acceptable to send SMTP responses divided
> over several TCP packets?

It is perfectly acceptable, although the converse is more commonly
seen, that is, multiple responses being sent in a single packet. (This
has also been known to cause problems with incompliant implementations.)

				Ned