IPv6 Reverse DNS

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IPv6 Reverse DNS

Martin Barry
Hi

I noted that postfix is writing headers with "unknown" instead of the IPv6
reverse DNS that I know exists.

e.g.

Received: from merboo.mamista.net (unknown [IPv6:2001:470:1f0b:1055::1])
        by tigger.mamista.net (Postfix) with ESMTP id 581F21100B4
        for <[hidden email]>; Mon, 22 Mar 2010 02:18:00 +1100 (EST)


$ dig -x 2001:470:1f0b:1055::1 +short
merboo.mamista.net.


I'm still convinced the problem is not with postfix but is there a way to
imitate it's IPv6 reverse DNS lookups so I can get closer to the cause of
the problem?

cheers
Marty
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Re: IPv6 Reverse DNS

Bernhard Schmidt
Martin Barry <[hidden email]> wrote:

Hi Martin,

> I noted that postfix is writing headers with "unknown" instead of the IPv6
> reverse DNS that I know exists.
>
> e.g.
>
> Received: from merboo.mamista.net (unknown [IPv6:2001:470:1f0b:1055::1])
>         by tigger.mamista.net (Postfix) with ESMTP id 581F21100B4
>         for <[hidden email]>; Mon, 22 Mar 2010 02:18:00 +1100 (EST)
>
>
> $ dig -x 2001:470:1f0b:1055::1 +short
> merboo.mamista.net.

$ dig -t aaaa merboo.mamista.net +short
2001:470:1f0a:1055::2

1f0a != 1f0b

Bernhard

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Re: IPv6 Reverse DNS

Olivier MJ Crepin-Leblond
In reply to this post by Martin Barry


Le 21/03/2010 16:32, Martin Barry a écrit :

> Hi
>
> I noted that postfix is writing headers with "unknown" instead of the IPv6
> reverse DNS that I know exists.
>
> e.g.
>
> Received: from merboo.mamista.net (unknown [IPv6:2001:470:1f0b:1055::1])
>         by tigger.mamista.net (Postfix) with ESMTP id 581F21100B4
>         for <[hidden email]>; Mon, 22 Mar 2010 02:18:00 +1100 (EST)
>
>
> $ dig -x 2001:470:1f0b:1055::1 +short
> merboo.mamista.net.
>
>
> I'm still convinced the problem is not with postfix but is there a way to
> imitate it's IPv6 reverse DNS lookups so I can get closer to the cause of
> the problem?
>
>  

I have no trouble with reverse IPv6 DNS in my postfix headers. Looks
like a local DNS config error or mis-delegation.
Either way, I don't think it's a postfix issue at all.

--
Olivier MJ Crépin-Leblond, PhD
http://www.gih.com/ocl.html

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Re: IPv6 Reverse DNS

Wietse Venema
In reply to this post by Martin Barry
Martin Barry:

> Hi
>
> I noted that postfix is writing headers with "unknown" instead of the IPv6
> reverse DNS that I know exists.
>
> e.g.
>
> Received: from merboo.mamista.net (unknown [IPv6:2001:470:1f0b:1055::1])
>         by tigger.mamista.net (Postfix) with ESMTP id 581F21100B4
>         for <[hidden email]>; Mon, 22 Mar 2010 02:18:00 +1100 (EST)
>
>
> $ dig -x 2001:470:1f0b:1055::1 +short
> merboo.mamista.net.
>
>
> I'm still convinced the problem is not with postfix but is there a way to
> imitate it's IPv6 reverse DNS lookups so I can get closer to the cause of
> the problem?

The reverse name must resolve to the client IP address. If they don't
match, Postfix will use the name "unknown", because the client name
is used for logging and may also be used for access decisions.

        Wietse
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Re: IPv6 Reverse DNS

Martin Barry
In reply to this post by Bernhard Schmidt
$quoted_author = "Bernhard Schmidt" ;
> >
> > $ dig -x 2001:470:1f0b:1055::1 +short
> > merboo.mamista.net.
>
> $ dig -t aaaa merboo.mamista.net +short
> 2001:470:1f0a:1055::2
>
> 1f0a != 1f0b

[facepalms]

thanks!
Marty