From owner-freebsd-chat Mon Feb 25 14:25:18 2002 Delivered-To: freebsd-chat@freebsd.org Received: from picard.skynet.be (picard.skynet.be [195.238.3.131]) by hub.freebsd.org (Postfix) with ESMTP id A8BE337B41A for ; Mon, 25 Feb 2002 14:25:09 -0800 (PST) Received: from [10.0.1.18] (ip-27.shub-internet.org [194.78.144.27] (may be forged)) by picard.skynet.be (8.11.6/8.11.6/Skynet-OUT-2.16) with ESMTP id g1PMOb809312; Mon, 25 Feb 2002 23:24:37 +0100 (MET) (envelope-from ) Mime-Version: 1.0 X-Sender: bs663385@pop.skynet.be Message-Id: In-Reply-To: <20020225161002.I47910@over-yonder.net> References: <4.3.2.7.2.20020224193235.01935ab8@threespace.com> <20020225161002.I47910@over-yonder.net> X-Grok: +++ath X-WebTV-Stationery: Standard; BGColor=black; TextColor=black Reply-By: Wed, 1 Jan 1984 12:34:56 +0100 X-Message-Flag: Outlook : A program to spread viri via e-mail. Try Eudora (http://www.eudora.com/), mutt (http://www.mutt.org/), or pine (http://www.washington.edu/pine/). But please, get something other than Outlook. Date: Mon, 25 Feb 2002 23:24:02 +0100 To: "Matthew D. Fuller" , "Jeremy C. Reed" From: Brad Knowles Subject: Re: blocked mail Cc: Chip Morton , FreeBSD Chat Content-Type: text/plain; charset="us-ascii" ; format="flowed" Sender: owner-freebsd-chat@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.org 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 ): >> 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, Do you hate Microsoft? Do you hate Outlook? Then visit the Anti-Outlook page at 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