Re: What does Postfix do with a 554 on connection?
- Reindl Harald:
> Am 20.03.2013 00:54, schrieb Wietse Venema:As of RFC 2821,
> > Reindl Harald:
> >>> I don't think that Postfix has ever distinguished between 5xx codes
> >>> at this protocol stage. The documentation says:
> >>> smtp_skip_5xx_greeting (default: yes)
> >>> Skip remote SMTP servers that greet with a 5XX status code
> >>> (go away, do not try again later).
> >>> By default, the Postfix SMTP client moves on the next mail
> >>> exchanger. Specify "smtp_skip_5xx_greeting = no" if Postfix
> >>> should bounce the mail immediately. The default setting is
> >>> incorrect, but it is what a lot of people expect to happen
> >> now i am more confused as before
> >> what the documentation above and the description says is not to
> >> bounce it, the RFC seems to indicate this too, so i do not get
> >> "The default setting is incorrect" in my picture
> > As I wrote, I will update the documentation which predates the
> > time that 554 was a defined greeting code
> sorry if i sound stupid this time
> should it be bounced and unsubscribed or left in the newsletter-list?
> from a users point of view "greeting code" is vague
The SMTP protocol allows a server to formally reject a transaction
while still allowing the initial connection as follows: a 554
response MAY be given in the initial connection opening message
instead of the 220. A server taking this approach MUST still wait
for the client to send a QUIT (see section 184.108.40.206) before closing
the connection and SHOULD respond to any intervening commands with
"503 bad sequence of commands". Since an attempt to make an SMTP
connection to such a system is probably in error, a server returning
a 554 response on connection opening SHOULD provide enough
information in the reply text to facilitate debugging of the sending
My plan is to remove smtp_skip_5xx_greeting because for the past
10+ years it is no longer a valid response to bounce mail.
Now, it is possible that some SMTP client implementations treat it
as a bounce response, but those clients are out of spec.