Subject: Re: [spfbis] WGLC: draft-ietf-spfbis-4408bis-14

From: Scott Kitterman <[email-masked]>
Date: Fri, 17 May 2013 02:48:04 -0400

On Wednesday, April 24, 2013 12:26:29 AM John Levine wrote:
> >The "Some implementations ..." sentence seems to be malformed.  I can't
> >parse it.
> 
> That whole paragraph could be replaced by "the result of evaluating
> check_host() with a syntactically invalid domain is undefined."

Perfect.  Thanks and done locally.

Scott K

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From: Stuart D Gathman <[email-masked]>
Date: Fri, 17 May 2013 12:34:09 -0400

> Perfect.  Thanks and done locally.
I thought 4408 made the result of a syntactically invalid domain 
"None".  There is code in pyspf and rfc4408 test suite that ensures the 
result is None for too long labels, and such.

rfc4408 4.3:
If the <domain> is malformed (label longer than 63 characters, 
zero-length label not at the end, etc.) or is not a fully qualified 
domain name, or if the DNS lookup returns "domain does not exist" (RCODE 
3), check_host() immediately returns the result "None".

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From: Scott Kitterman <[email-masked]>
Date: Fri, 17 May 2013 13:06:13 -0400

> result is None for too long labels, and such.

IIRC, the test suite has a non-preferred, but acceptable alternative.

> 3), check_host() immediately returns the result "None".

The trick is that not everyone does that.  Sometimes you get a permerror out 
of it, so you can't rely on it.

Scott K