nanog mailing list archives
Re: IPv6 isn't SMTP
From: Franck Martin <fmartin () linkedin com>
Date: Thu, 27 Mar 2014 02:16:40 +0000
On Mar 26, 2014, at 5:47 PM, Fred Baker (fred) <fred () cisco com> wrote:
On Mar 25, 2014, at 8:31 PM, Cutler James R <james.cutler () consultant com> wrote:3. Arguing about IPv6 in the context of requirements upon SMTP connections is playing that uncomfortable game with one’s own combat boots. And not particularly productive.That is one of my two big take-aways from this conversation. The other is that operators of SMTP MTAs should implement RDNS for them, which I thought we already knew.
It is in several industry recommendations cf for instance BCP at www.m3aawg.org
To my knowledge, there are three impacts that IPv6 implementation makes on an SMTP implementation. One is that the OS interface to get the address of the next MUA or MTA needs to use getaddrinfo() instead of gethostbyname() (and would do well to observe RFC 6555’s considerations). Another is that, whether on an incoming or an outbound connection, when the application gets its own address from the OS (binary or as a character string), it needs to allocate more storage for the data structure. The third is that it needs to be able to interpret user@2001:db8::1 as well as user@dns-name and user@192.0.2.1.
and user@2001:db8::1.25 with user@192.0.2.1:25. Who had the good idea to use : for IPv6 addresses while this is the separator for the port in IPv4? A few MTA are confused by it.
All things considered, that’s a pretty narrow change set. Everyone here, no doubt, is clueful enough to implement RDNS for their MTAs. We know that there are people in the world that don’t implement it for IPv4. Yet, here we are, using SMTP/IPv4 to discuss this, and I don’t hear anyone saying that IPv4 isn’t ready for prime time as a result of the fact of some operators not implementing RDNS.
There is some confusion between MX selection and address selection, I tried to document it, and resolve the ambiguities in http://datatracker.ietf.org/doc/draft-martin-smtp-target-host-selection-ipv4-IPv6/ (comments at apps-discuss () ietf org) Remember 70 to 90% of email is spam, blacklists can drop as much as 75% of spam at connection time (an IPv6 blacklist has problems due to size and impact on DNS). If we mess up the transition of SMTP to IPv6, less than 1 out of 10 emails in your mailbox will be remotely interesting….
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Current thread:
- Re: IPv6 isn't SMTP, (continued)
- Re: IPv6 isn't SMTP Clay Fiske (Mar 27)
- Re: IPv6 isn't SMTP Blake Hudson (Mar 28)
- Re: IPv6 isn't SMTP Dave Crocker (Mar 27)
- Re: IPv6 isn't SMTP Lamar Owen (Mar 27)
- Re: IPv6 isn't SMTP Fred Baker (fred) (Mar 26)
- Re: IPv6 isn't SMTP James R Cutler (Mar 26)
- Re: IPv6 isn't SMTP John Levine (Mar 26)
- Re: IPv6 isn't SMTP Tony Finch (Mar 27)
- Re: IPv6 isn't SMTP Enno Rey (Mar 27)
- Re: IPv6 isn't SMTP John R. Levine (Mar 27)
- Re: IPv6 isn't SMTP Franck Martin (Mar 26)
- Re: IPv6 isn't SMTP Robert Drake (Mar 26)
- Re: IPv6 address literals probably aren't SMTP either John Levine (Mar 26)
- Re: IPv6 address literals probably aren't SMTP either Robert Drake (Mar 26)
- Re: IPv6 address literals probably aren't SMTP either John R. Levine (Mar 26)
- Re: IPv6 isn't SMTP Owen DeLong (Mar 26)
- Re: IPv6 isn't SMTP Franck Martin (Mar 27)
- Re: IPv6 isn't SMTP Owen DeLong (Mar 27)
- Re: IPv6 isn't SMTP Tony Finch (Mar 27)
- Re: IPv6 isn't SMTP Jimmy Hess (Mar 25)