Re: Last Call: draft-klensin-rfc2821bis
Douglas Otis <dotis@mail-abuse.org> Fri, 28 March 2008 11:21 UTC
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From: Douglas Otis <dotis@mail-abuse.org>
To: Keith Moore <moore@network-heretics.com>
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Subject: Re: Last Call: draft-klensin-rfc2821bis
Date: Fri, 28 Mar 2008 01:20:55 -1000
References: <Pine.LNX.4.33.0803272156270.29413-100000@egate.xpasc.com> <47EC90AB.90304@network-heretics.com>
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On Mar 27, 2008, at 8:31 PM, Keith Moore wrote: > David Morris wrote: >> >> Perhaps you could help us out and share a reference to >> documentation of such problems. I for one have not personally >> observed any problems related to using the A record to locate a >> mail server when there is no MX. > > part of the problem is that most hosts don't wish to receive mail > but there is no way to indicate this to a mailer that is trying to > deliver mail to them. Agreed. Although MX records provide a discovery method for SMTP services, fall-back to A records prevents an assertion of no SMTP services when A records exist at the domain. > if the host has an A record, under the current specifications, a > mailer that gets a message (presumably spam) with a recipient > address at that domain is expected to try to deliver that message. > and unless that host implements a dummy SMTP server that refuses all > incoming mail with a permanent error the sending mailer will keep > getting "connection refused" - which is treated as a temporary error > and the sending mailer will keep retrying. this clogs up mail queues. As John Levine pointed out, a message with an originating email- address referencing a domain only containing AAAA records is likely to be refused. In part to avoid potential issues handing NDNs as Frank suggested, and in part that each IPv6 hostname offers a vast number of domains and addresses that can be exploited as a spoofed source due to the RFC2821bis fallback specifically including IPv6 AAAA records. > and the dummy SMTP server works, but it consumes resources on the > host and eats bandwidth on the network. having a way to say "don't > send this host any mail" in DNS seems like a useful thing. and we > simply don't need the fallback to AAAA because we don't have the > backward compatibility issue that we had when MX records were > introduced. Not sanctioning IPv6 AAAA records as an MX fall-back avoids the undesired traffic now caused by SMTP spoofing of A records. MX records might then be seen as an opt-in mechanism from the perspective of IPv6, since opt-out mechanism are onerous for those not wishing to participate. While Bill and others expressed concerns of being tied to DNS, whatever replaces DNS must also offer separate service and IP address resolution mechanisms. The concerns related to DNS seems to assume there would not be separate service/address mechanisms, but this would not suit those running their services out of different domains. Not sanctioning IPv6 MX to AAAA fallback actually makes IPv6 easier to manage in that email policies will not be required at all IPv6 hostnames, as they would be for IPv4. Those wanting to employ small and simple services connected directly to the Internet might otherwise find these services inundated by undesired traffic whenever their hostname is used to spoof an email source. Not sanctioning IPv6 MX to AAAA fallback makes IPv6 safer from abuse, perhaps enough to compensate for the quadrillions of hostnames and IP addresses that might be involved. Over time SMTP itself may not remain viable as an exchange between anonymous parties if RFC2821bis retains IPv6 AAAA records as a fall-back for MX records. -Doug _______________________________________________ IETF mailing list IETF@ietf.org https://www.ietf.org/mailman/listinfo/ietf
- RE: Last Call: draft-klensin-rfc2821bis (Simple M… Hollenbeck, Scott
- Re: Last Call: draft-klensin-rfc2821bis (Simple M… Frank Ellermann
- Re: Last Call: draft-klensin-rfc2821bis (Simple M… Frank Ellermann
- Re: Last Call: draft-klensin-rfc2821bis (Simple M… Frank Ellermann
- Re: Last Call: draft-klensin-rfc2821bis (Simple M… Pete Resnick
- Re: Last Call: draft-klensin-rfc2821bis (Simple M… Ned Freed
- Re: Last Call: draft-klensin-rfc2821bis (Simple M… Frank Ellermann
- Re: Last Call: draft-klensin-rfc2821bis (Simple M… Dave Crocker
- Re: Last Call: draft-klensin-rfc2821bis (Simple M… Frank Ellermann
- Re: Last Call: draft-klensin-rfc2821bis (Simple M… John C Klensin
- Re: Last Call: draft-klensin-rfc2821bis (Simple M… Ned Freed
- Lists and aliases (Re: Last Call: draft-klensin-r… Harald Tveit Alvestrand
- Re: Last Call: draft-klensin-rfc2821bis (Simple M… Pete Resnick
- Re: Lists and aliases (Re: Last Call: draft-klens… Ned Freed
- Re: Lists and aliases (Re: Last Call: draft-klens… Tony Finch
- Re: Lists and aliases (Re: Last Call: draft-klens… Ned Freed
- Last Call: draft-klensin-rfc2821bis (Simple Mail … Frank Ellermann
- Re: Last Call: draft-klensin-rfc2821bis (Simple M… Ned Freed
- Re: Last Call: draft-klensin-rfc2821bis (Simple M… John C Klensin
- Re: Last Call: draft-klensin-rfc2821bis (Simple M… Frank Ellermann
- Re: Last Call: draft-klensin-rfc2821bis (Simple M… Ned Freed
- Re: Last Call: draft-klensin-rfc2821bis (Simple M… Pekka Savola
- Re: Last Call: draft-klensin-rfc2821bis Frank Ellermann
- Re: Last Call: draft-klensin-rfc2821bis Douglas Otis
- Re: Last Call: draft-klensin-rfc2821bis John C Klensin
- Re: Last Call: draft-klensin-rfc2821bis Mark Andrews
- Re: Last Call: draft-klensin-rfc2821bis John C Klensin
- Re: Last Call: draft-klensin-rfc2821bis Douglas Otis
- Re: Last Call: draft-klensin-rfc2821bis John C Klensin
- Re: Last Call: draft-klensin-rfc2821bis John Leslie
- Re: Last Call: draft-klensin-rfc2821bis Ned Freed
- Re: Last Call: draft-klensin-rfc2821bis Frank Ellermann
- Re: Last Call: draft-klensin-rfc2821bis Douglas Otis
- Re: Last Call: draft-klensin-rfc2821bis Ned Freed
- Re: Last Call: draft-klensin-rfc2821bis Keith Moore
- Re: Last Call: draft-klensin-rfc2821bis Frank Ellermann
- Re: Last Call: draft-klensin-rfc2821bis Bill Manning
- Re: Last Call: draft-klensin-rfc2821bis Frank Ellermann
- Re: Last Call: draft-klensin-rfc2821bis Mark Andrews
- Re: Last Call: draft-klensin-rfc2821bis Bill Manning
- Re: Last Call: draft-klensin-rfc2821bis Bill Manning
- Re: Last Call: draft-klensin-rfc2821bis Ned Freed
- Re: Last Call: draft-klensin-rfc2821bis Ned Freed
- Re: Last Call: draft-klensin-rfc2821bis Willie Gillespie
- Re: Last Call: draft-klensin-rfc2821bis Mark Andrews
- Re: Last Call: draft-klensin-rfc2821bis Keith Moore
- Re: Last Call: draft-klensin-rfc2821bis John C Klensin
- Re: Last Call: draft-klensin-rfc2821bis Keith Moore
- Re: Last Call: draft-klensin-rfc2821bis Ned Freed
- Re: Last Call: draft-klensin-rfc2821bis Ned Freed
- Re: Last Call: draft-klensin-rfc2821bis Ned Freed
- Re: Last Call: draft-klensin-rfc2821bis Keith Moore
- Re: Last Call: draft-klensin-rfc2821bis Markku Savela
- Re: Last Call: draft-klensin-rfc2821bis Ned Freed
- RE: Last Call: draft-klensin-rfc2821bis Hallam-Baker, Phillip
- Re: Last Call: draft-klensin-rfc2821bis Keith Moore
- Re: Last Call: draft-klensin-rfc2821bis SM
- Re: Last Call: draft-klensin-rfc2821bis Bill Manning
- Re: Last Call: draft-klensin-rfc2821bis Keith Moore
- Re: Last Call: draft-klensin-rfc2821bis Mark Andrews
- Re: Last Call: draft-klensin-rfc2821bis SM
- Re: Last Call: draft-klensin-rfc2821bis John C Klensin
- Re: Last Call: draft-klensin-rfc2821bis SM
- Re: Last Call: draft-klensin-rfc2821bis Pekka Savola
- Re: Last Call: draft-klensin-rfc2821bis Mark Andrews
- Re: Last Call: draft-klensin-rfc2821bis Frank Ellermann
- Re: Last Call: draft-klensin-rfc2821bis Keith Moore
- Re: Last Call: draft-klensin-rfc2821bis Bill Manning
- Implicit MX and A RRs (was: Re: Last Call: draft-… John C Klensin
- Re: Last Call: draft-klensin-rfc2821bis Frank Ellermann
- Re: Last Call: draft-klensin-rfc2821bis Mark Andrews
- Re: Last Call: draft-klensin-rfc2821bis Frank Ellermann
- Re: Implicit MX and A RRs Tony Hansen
- Re: Last Call: draft-klensin-rfc2821bis John Levine
- Re: Last Call: draft-klensin-rfc2821bis Frank Ellermann
- Re: Last Call: draft-klensin-rfc2821bis John C Klensin
- Re: Last Call: draft-klensin-rfc2821bis Tony Finch
- Re: Last Call: draft-klensin-rfc2821bis Keith Moore
- Re: Last Call: draft-klensin-rfc2821bis Keith Moore
- Re: Last Call: draft-klensin-rfc2821bis John Levine
- Re: Last Call: draft-klensin-rfc2821bis Eliot Lear
- RE: Last Call: draft-klensin-rfc2821bis Tony Hain
- Re: Last Call: draft-klensin-rfc2821bis Keith Moore
- Re: Last Call: draft-klensin-rfc2821bis Keith Moore
- Re: Last Call: draft-klensin-rfc2821bis Dave Crocker
- Re: Last Call: draft-klensin-rfc2821bis Keith Moore
- Re: Last Call: draft-klensin-rfc2821bis Keith Moore
- RE: Last Call: draft-klensin-rfc2821bis Hallam-Baker, Phillip
- Re: Last Call: draft-klensin-rfc2821bis Willie Gillespie
- IPv6 incentive? RE: Last Call: draft-klensin-rfc2… Hallam-Baker, Phillip
- Re: Last Call: draft-klensin-rfc2821bis Frank Ellermann
- Re: Last Call: draft-klensin-rfc2821bis Jim Fenton
- Re: Last Call: draft-klensin-rfc2821bis David Conrad
- RE: Last Call: draft-klensin-rfc2821bis Tony Hain
- Re: Last Call: draft-klensin-rfc2821bis Dave Crocker
- Re: Last Call: draft-klensin-rfc2821bis Frank Ellermann
- Re: Last Call: draft-klensin-rfc2821bis Keith Moore
- RE: Last Call: draft-klensin-rfc2821bis Hallam-Baker, Phillip
- RE: Last Call: draft-klensin-rfc2821bis Tony Hain
- RE: Last Call: draft-klensin-rfc2821bis John C Klensin
- Re: Implicit MX and A RRs John C Klensin
- Re: Implicit MX and A RRs Matti Aarnio
- RE: Last Call: draft-klensin-rfc2821bis John C Klensin
- Re: Last Call: draft-klensin-rfc2821bis Mark Andrews
- Re: Implicit MX and A RRs Tony Finch
- Re: Last Call: draft-klensin-rfc2821bis Ned Freed
- Re: Last Call: draft-klensin-rfc2821bis Mark Andrews
- Re: Last Call: draft-klensin-rfc2821bis Joe Abley
- Re: Last Call: draft-klensin-rfc2821bis Mark Andrews
- Re: Last Call: draft-klensin-rfc2821bis John C Klensin
- Re: Last Call: draft-klensin-rfc2821bis Keith Moore
- Re: Last Call: draft-klensin-rfc2821bis David Morris
- Re: Last Call: draft-klensin-rfc2821bis Keith Moore
- Re: Implicit MX and A RRs Keith Moore
- RE: Last Call: draft-klensin-rfc2821bis michael.dillon
- Re: Last Call: draft-klensin-rfc2821bis Douglas Otis
- Re: Last Call: draft-klensin-rfc2821bis John C Klensin
- Re: Last Call: draft-klensin-rfc2821bis Keith Moore
- Re: Last Call: draft-klensin-rfc2821bis Ned Freed
- Re: Implicit MX and A RRs Ned Freed
- Re: Last Call: draft-klensin-rfc2821bis Frank Ellermann
- Re: Last Call: draft-klensin-rfc2821bis John C Klensin
- Re: Last Call: draft-klensin-rfc2821bis Keith Moore
- Re: Last Call: draft-klensin-rfc2821bis Ned Freed
- Re: Last Call: draft-klensin-rfc2821bis Frank Ellermann
- Re: Last Call: draft-klensin-rfc2821bis Pekka Savola
- Re: Last Call: draft-klensin-rfc2821bis John C Klensin
- Re: Last Call: draft-klensin-rfc2821bis Pekka Savola
- Re: Last Call: draft-klensin-rfc2821bis Frank Ellermann
- Re: Last Call: draft-klensin-rfc2821bis Ned Freed
- Re: Last Call: draft-klensin-rfc2821bis Keith Moore
- Re: Last Call: draft-klensin-rfc2821bis Dave Crocker
- Re: Last Call: draft-klensin-rfc2821bis Keith Moore
- Re: Last Call: draft-klensin-rfc2821bis Theodore Tso
- Re: Last Call: draft-klensin-rfc2821bis Frank Ellermann
- Re: Last Call: draft-klensin-rfc2821bis Henning Schulzrinne
- Re: Last Call: draft-klensin-rfc2821bis John Levine
- Re: Last Call: draft-klensin-rfc2821bis SM
- Re: Last Call: draft-klensin-rfc2821bis Keith Moore
- Re: Last Call: draft-klensin-rfc2821bis SM
- Re: Last Call: draft-klensin-rfc2821bis John Levine
- Re: Last Call: draft-klensin-rfc2821bis Dave Crocker
- Re: Last Call: draft-klensin-rfc2821bis Henning Schulzrinne
- Re: Last Call: draft-klensin-rfc2821bis David Morris
- Re: Last Call: draft-klensin-rfc2821bis Dave Crocker
- Re: Last Call: draft-klensin-rfc2821bis Mark Andrews
- Re: Last Call: draft-klensin-rfc2821bis Keith Moore
- Re: Last Call: draft-klensin-rfc2821bis John C Klensin
- Re: Last Call: draft-klensin-rfc2821bis Keith Moore
- Re: Last Call: draft-klensin-rfc2821bis Tony Finch
- Re: Last Call: draft-klensin-rfc2821bis Henning Schulzrinne
- Re: Last Call: draft-klensin-rfc2821bis Bill Manning
- Re: Last Call: draft-klensin-rfc2821bis Dave Crocker
- Re: Last Call: draft-klensin-rfc2821bis Keith Moore
- Re: Last Call: draft-klensin-rfc2821bis: closing … Tony Hansen
- Re: Last Call: draft-klensin-rfc2821bis: closing … Dave Crocker
- Re: Last Call: draft-klensin-rfc2821bis: closing … Keith Moore
- Re: Last Call: draft-klensin-rfc2821bis: closing … Lisa Dusseault
- Re: Last Call: draft-klensin-rfc2821bis: closing … Douglas Otis
- Re: Last Call: draft-klensin-rfc2821bis: closing … Hector Santos
- Re: Last Call: draft-klensin-rfc2821bis: closing … Henning Schulzrinne
- Re: Last Call: draft-klensin-rfc2821bis: closing … Dave Crocker
- Re: Last Call: draft-klensin-rfc2821bis: closing … Paul Smith
- Re: Last Call: draft-klensin-rfc2821bis: closing … Keith Moore
- Re: Last Call: draft-klensin-rfc2821bis: closing … Tom.Petch
- Re: Last Call: draft-klensin-rfc2821bis: closing … Hector Santos
- Re: Last Call: draft-klensin-rfc2821bis: closing … Robert A. Rosenberg