Re: problem dealing w/ ietf.org mail servers

you are not the first to report this problem.

On Wed, Jul 02, 2008 at 10:47:53PM -0700, 'kent' wrote:
> Hi Rich
> 
> I'll cc this to the ietf list, as you suggested.
> 
> I've found the problem.  It may or may not be something that ietf want's to
> do something about -- I would think they would, since it seems to have global
> significance.  But I can fix it from this end. 
> 
> Specifically, the problem Dave encountered earlier was that the ietf mail
> server was rejecting mail without reverse dns, and since the ietf mail server
> and the mipassoc.org/dkim.org/bbiw.net mail servers all had ip6 addresses,
> and ip6 is used preferentially, and I hadn't set up reverse dns, they were
> dropping all mail.  I fixed that, and things started working. 
> 
> The only domains I control that had explicit ipv6 addresses were Dave's
> domains.  For example, graybeards.net:
> 
>     # host graybeards.net
>     graybeards.net has address 72.52.113.69
>     graybeards.net has IPv6 address 2001:470:1:76:0:ffff:4834:7145
>     graybeards.net mail is handled by 10 mail.graybeards.net.
>     # host mail.graybeards.net
>     mail.graybeards.net has address 72.52.113.69
>     mail.graybeards.net has IPv6 address 2001:470:1:76:0:ffff:4834:7145
>     # host 2001:470:1:76:0:ffff:4834:7145
>     5.4.1.7.4.3.8.4.f.f.f.f.0.0.0.0.6.7.0.0.1.0.0.0.0.7.4.0.1.0.0.2.ip6.arpa domain name pointer mail.graybeards.net.
>     #
> 
> Mail now works for this domain.
> 
> But, it turns out, the ietf.org mail servers are rejecting mail from other
> domains as well.  Here's a log entry for one of your messages:
> 
> Jul  2 13:10:23 mail sendmail[31264]: STARTTLS=client, relay=mail.ietf.org., 
>     version=TLSv1/SSLv3, verify=FAIL, cipher=DHE-RSA-AES256-SHA, bits=256/256
> Jul  2 13:10:29 mail sendmail[31264]: m62Hvfbm011799: to=<enum@ietf.org>, 
>     ctladdr=<richard@shockey.us> (1023/1023), delay=02:12:32, xdelay=00:00:28, 
>     mailer=esmtp, pri=662167, relay=mail.ietf.org. [IPv6:2001:1890:1112:1::20], dsn=4.7.1, 
>     stat=Deferred: 450 4.7.1 Client host rejected: cannot find your reverse hostname, [2001:470:1:76:2c0:9fff:fe3e:4009]
> 
> Rejecting when you can't find a reverse is, of course, a common anti-spam 
> technique. 
> 
> However, this last address, 2001:470:1:76:2c0:9fff:fe3e:4009, is not
> explicitly configured on the sending server; instead, it is being implicitly
> configured through ip6 autoconf stuff:
> 
>     eth0      Link encap:Ethernet  HWaddr 00:C0:9F:3E:40:09  
>               inet addr:72.52.113.176  Bcast:72.52.113.255  Mask:255.255.255.0
>               inet6 addr: fe80::2c0:9fff:fe3e:4009/64 Scope:Link
>               inet6 addr: 2001:470:1:76:2c0:9fff:fe3e:4009/64 Scope:Global
> 
> The 2 ip6 addresses, the link-local address, and the global address, are
> generated from the mac address (you can see the 0x4009 at the end) and
> configured autmomatically, merely because ipv6 is enabled on this box by
> default, and a global prefix is available.
> 
> That is to say, it appears the ietf.org mail server is probably now rejecting
> mail from *any* box that is getting a default global ipv6 address, since
> those addresses will most likely not be in ip6.arpa.  There may be a whole
> lot of boxes in this situation. 
> 
> Kent
> 
> PS -- I'm not sure this will actually make it to the ietf list :-) ...
> _______________________________________________
> Ietf mailing list
> Ietf@ietf.org
> https://www.ietf.org/mailman/listinfo/ietf

-- 
--bill

Opinions expressed may not even be mine by the time you read them, and
certainly don't reflect those of any other entity (legal or otherwise).

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