a matter of curiosity....
I have a tool running that tries to verify email addresses (reasons
irrelevant here) - the sequence of commands used is EHLO, MAIL FROM, RCPT
TO, RSET, QUIT (VRFY being more-or-less useless these days).
I noticed that a few large sites are returning 554 on the RSET, with the
text "Transaction failed" - hotmail.com in particular.
Now, this is obviously in violation of RFC 2821, but I wonder..... does
anyone have any idea of why they're doing that?
Offhand, I see two possibilities:
(1) Someone is very confused about what SMTP statuses mean. Yes, sending a
RSET in the middle of a transaction causes the transaction to fail. But
the response to a RSET or any other command is supposed to indicate the
result of processing that specific command, not what the command did
to the current transaction.
(2) The intent was to limit the number of transactions per connection (to 1)
and the implementation was seriously botched.