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Re: Re: IPv6 with 'a' or do we need 'aaaa' ?

2005-05-26 06:12:29
In 
<1117112703(_dot_)11886(_dot_)64(_dot_)camel(_at_)firenze(_dot_)zurich(_dot_)ibm(_dot_)com>
 Jeroen Massar <jeroen(_at_)unfix(_dot_)org> writes:

On Thu, 2005-05-26 at 13:38 +0200, Frank Ellermann wrote:
Jeroen Massar wrote:
<SNIP>
what about host.example.com/24 IPv4 or IPv6?

[explanation deleted]

It is a really odd way to write it, but then it is at least defined.

Thus: "v=spf1 a:host.example.com// -all"

That would be a syntax error because there isn't a number following
the "//".  


Means host.example.com/32 in IPv4 + host.example.com/128 in IPv6 is
allowed to send and not anything else?

This is what you get if you have just "a:host.example.com"


The big remaining question then still is, what happens with the above
when host.example.com sends a mail outbound and the receiving end
doesn't have IPv6 SPF capabilities...

Well, if the receiving MTA doesn't support IPv6, then the connection
MUST be IPv4 and therefore only IPv4 checks will be done.


As mentioned in another recent thread, there have been IPv6 SPF
implementations out in the wild for over a year now, people are using
SPF and IPv6, the SPF spec appears to be well defined for IPv6, but
like many things related to IPv6, it hasn't been tested as much as
IPv4.  If you understand IPv6 and can use and test SPF using IPv6, I
would greatly appreciate it if you did a bunch of testing.



-wayne


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