Murray S. Kucherawy wrote:
Someone else suggested nothing parses SMTP replies beyond the three digits.
That's not true in ESMTP; the enhanced status codes (if used) and the reply to
EHLO itself are structured.
Not to keep piling on, but RFC 2920 (pipelining) says the server SHOULD
structure the text responses so that the client can pair up commands and
responses.
John suggested a new reply code series, but that scares me a bit; what would a
staunch legacy implementation be likely to do with that?
It would infer that it was talking to something other than an SMTP
server, and drop the connection as rapidly as possible to avoid doing
further damage.
Before we try anything like that, we need actual feature negotiation
(not just announcements), which ESMTP lacks.
<csg>