On Mon, 2003-12-08 at 19:53 +0000, Russell King wrote:
> Now, the interesting thing is that RFC2821 section 4.5.1 says:
>
> Any system that includes an SMTP server supporting mail relaying or
> delivery MUST support the reserved mailbox "postmaster" as a case-
> insensitive local name. This postmaster address is not strictly
> necessary if the server always returns 554 on connection opening (as
> described in section 3.1). The requirement to accept mail for
> postmaster implies that RCPT commands which specify a mailbox for
> postmaster at any of the domains for which the SMTP server provides
> mail service, as well as the special case of "RCPT TO:<Postmaster>"
> (with no domain specification), MUST be supported.
You missed a bit:
SMTP systems are expected to make every reasonable effort to accept
mail directed to Postmaster from any other system on the Internet.
In extreme cases --such as to contain a denial of service attack or
other breach of security-- an SMTP server may block mail directed to
Postmaster. However, such arrangements SHOULD be narrowly tailored
so as to avoid blocking messages which are not part of such attacks.
That was enough for me to double-check that my systems are accepting it.
Unfortunately, it's not working correctly for IPv6 -- it shares the same
IPv6 domain literal bug as was fixed in EHLO syntax checking in 4.30:
The HELO response probably wants changing too.
220 canuck.infradead.org ESMTP Exim 4.30 Tue, 09 Dec 2003 04:05:19 -0500
HELO ME
250 canuck.infradead.org Hello me [2002:c1ed:8229::1]
MAIL FROM:<>
250 OK
RCPT TO:<postmaster@???>
250 Accepted
RCPT TO:<postmaster@[IPv6:2002:c1ed:8229::1]>
501 <postmaster@[IPv6:2002:c1ed:8229::1]>: malformed domain literal
RCPT TO:<postmaster@[2002:c1ed:8229::1]>
250 Accepted
--
dwmw2
