spf-discuss
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Re: ClassMates.com

2004-12-04 15:56:11
On Fri, 3 Dec 2004, Meng Weng Wong wrote:

On Fri, Dec 03, 2004 at 05:52:06PM -0500, Stuart D. Gathman wrote:
| 
| The point is to cause infinite recursion, and thereby cause mail to be
| rejected (provided client rejects on resource limit exceptions).
| 
| Most implementations will give SPF pass for legit mail.  The infinite
| recursion will only show up when the mail is from a spammer.  A very
| unfriendly to receiver policy.
| 

i'm not sure what the practical problem is with infinite
recursion.  loop detection is trivial and all spf
implementations i know of implement it.

The problem is it makes you do 20 (or whatever your limit is) DNS lookups
instead of 1 or 2.  I.e., it wastes the receivers resources.
The waste can be significant if the domain is commonly spammed.

-- 
              Stuart D. Gathman <stuart(_at_)bmsi(_dot_)com>
    Business Management Systems Inc.  Phone: 703 591-0911 Fax: 703 591-6154
"Confutatis maledictis, flamis acribus addictis" - background song for
a Microsoft sponsored "Where do you want to go from here?" commercial.


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