Date: Wed, 10 Oct 2001 10:54:42 -0700 (PDT) From: "Jeremy C. Reed" <reed@reedmedia.net> To: Szilveszter Adam <sziszi@bsd.hu> Cc: freebsd-advocacy@freebsd.org Subject: Re: advocacy/31194: freebsd.org mailing lists - configuration problem? Message-ID: <Pine.LNX.4.21.0110101027190.3559-100000@pilchuck.reedmedia.net> In-Reply-To: <200110101204.f9AC4b530689@freefall.freebsd.org>
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(Not sent to gnats. I understand this is closed, but I do have a few
comments.)
On Wed, 10 Oct 2001, Szilveszter Adam wrote:
> The symptom is that the message is rejected with a transitional error of:
>
> Helo command rejected; host not found and with an error code of 450 (I
> think)
Yes. It is a 450.
220 hub.freebsd.org ESMTP Postfix (Postfix Rules!)
helo pilchuck
250 hub.freebsd.org
mail from: <reed@reedmedia.net>
250 Ok
rcpt to: <thisshouldbounce@freebsd.org>
450 <pilchuck>: Helo command rejected: Host not found
quit
221 Bye
Just for your information, this is suggested in RFC 2821 (which obsoletes
821):
The argument field contains the fully-qualified domain name
of the SMTP client if one is available. In situations in which the SMTP
client system does not have a meaningful domain name (e.g., when its
address is dynamically allocated and no reverse mapping record is
available), the client SHOULD send an address literal ...
If the problem had to do with reverse lookups that didn't match up, then:
An SMTP server MAY verify that the domain name parameter in the EHLO
command actually corresponds to the IP address of the client. However,
the server MUST NOT refuse to accept a message for this reason if the
verification fails: the information about verification failure is for
logging and tracing only.
> Watch the transitory error messages come back for a few a days until
> your SMTP server gives up and the message fails.
...
> Also, leaving a message in limbo for several days is not exactly a
> great idea when you know that you won't accept it ever.
But I don't think this part of your comments were answered.
It seems like the mail server should not return a temporary error.
I am not sure why the 450 "Helo command rejected: Host not found" occured
after the "RCPT TO".
I believe it should occur directly at the HELO (OR EHLO) with a permanent
error, i.e.:
helo pilchuck
500 <pilchuck>: Helo command rejected: Host not found
(The RFC says: "If the EHLO command is not acceptable to the SMTP server,
501, 500, or 502 failure replies MUST be returned as appropriate.")
Jeremy C. Reed -- who is thinking about configuring his mail servers to
log and then maybe reject invalid HELOs to try to
stop more spam ...
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