On 3 Apr 2000, Lorens Kockum wrote:
> I have transmitted your point of view to Renaud, who responded
> that instead of a 550 for EXPN (Failure) he expected 500,
> 501, 502, 504 (Error). Sendmail and postfix send 502. After
> reviewing the RFC wrt exim's behaviour, he has patched nessus
> accordingly (cvs/nessus-plugins/scripts/sendmail_expn.nasl).
I tend to work from the revised RFC (which is not yet an RFC,
unfortunately). What it says is
550 Requested action not taken: mailbox unavailable
(e.g., mailbox not found, no access, or command rejected
for policy reasons)
It's that "command rejected for policy reasons" that I used. It is more
accurate than
500 syntax error, command unrecognized
502 command not implemented
504 command parameter not implemented
Of course, the list in RFC 821 and in the new RFC both show the folly of
trying to anticipate all the new circumstances that are going to arise.
Trying to be clever with them takes the "S" out of SMTP. IMHO, of
course.
--
Philip Hazel University of Cambridge Computing Service,
ph10@??? Cambridge, England. Phone: +44 1223 334714.
