Date: Mon, 25 Feb 2002 23:24:02 +0100 From: Brad Knowles <brad.knowles@skynet.be> To: "Matthew D. Fuller" <fullermd@over-yonder.net>, "Jeremy C. Reed" <reed@reedmedia.net> Cc: Chip Morton <tech_info@threespace.com>, FreeBSD Chat <chat@freebsd.org> Subject: Re: blocked mail Message-ID: <p0510140bb8a0699fc67e@[10.0.1.18]> In-Reply-To: <20020225161002.I47910@over-yonder.net> References: <4.3.2.7.2.20020224193235.01935ab8@threespace.com> <Pine.LNX.4.43.0202251158460.25937-100000@pilchuck.reedmedia.net> <20020225161002.I47910@over-yonder.net>
next in thread | previous in thread | raw e-mail | index | archive | help
At 4:10 PM -0600 2002/02/25, Matthew D. Fuller wrote: >> If you don't have an MX record then it tries the A record (which is the IP >> for the hostname). > > Not if your mailer follows the RFC's strictly. Re-read RFC 2821 (see <http://www.faqs.org/rfcs/rfc2821.html>): >> 5. Address Resolution and Mail Handling >> >> Once an SMTP client lexically identifies a domain to which mail >> will be delivered for processing (as described in sections 3.6 >> and 3.7), a DNS lookup MUST be performed to resolve the domain >> name [22]. The names are expected to be fully-qualified domain >> names (FQDNs): mechanisms for inferring FQDNs from partial names >> or local aliases are outside of this specification and, due to a >> history of problems, are generally discouraged. The lookup first >> attempts to locate an MX record associated with the name. If a >> CNAME record is found instead, the resulting name is processed as >> if it were the initial name. If no MX records are found, but an >> A RR is found, the A RR is treated as if it was associated with >> an implicit MX RR, with a preference of 0, pointing to that host. >> If one or more MX RRs are found for a given name, SMTP systems >> MUST NOT utilize any A RRs associated with that name unless they >> are located using the MX RRs; the "implicit MX" rule above >> applies only if there are no MX records present. If MX records >> are present, but none of them are usable, this situation MUST be >> reported as an error. -- Brad Knowles, <brad.knowles@skynet.be> Do you hate Microsoft? Do you hate Outlook? Then visit the Anti-Outlook page at <http://www.rodos.net/outlook/>; and see how much fun you can have. "They that can give up essential liberty to obtain a little temporary safety deserve neither liberty nor safety." -Benjamin Franklin, Historical Review of Pennsylvania. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-chat" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?p0510140bb8a0699fc67e>