spf-discuss
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Re: Perfect Spam Blocking with SPF -- Update

2004-08-20 05:37:37
On Thu, Aug 19, 2004 at 07:27:57PM -0700, David Lawless wrote:
Now I define a false positive as when the sender of a bounced 
message calls me on the telephone.  If they are too clueless or 
unmotivated to comprehend the bounce message and/or find my 
phone number on the web-site, I didn't want to hear from them 
anyway.

I'm glad this works out for you. It wouldn't work out for me, since a 
prospective customer how tries and contact me might be thinking 'oh what the 
hell, i'll just look for someone else'.. I don't want to run that risk, being a 
starting entrepeneur and all..

One of the CPAN 'whois' modules normalizes most of the standard 
fields into a nifty structure.  This will be useful for checking 
the registration dates and registrar.  The rest I'll do ad-hoc.  
For example, private registration domains at Network solutions 
have a contact address like so:

  aq3zb2cp7bs(_at_)networksolutionsprivateregistration(_dot_)com

That's pretty easy to match out with a perl regex.  It's obvious 
that spammers will gravitate to the ultra-low-cost registrars 
like Godaddy.  I don't know ANYONE I want to correspond with who 
needs to buy their domain for $9.95 ($3 for bulk purchased 
domains; I'll bet $1 can be negotiated if you're willing to buy 
1000+ domains).  If one turns up, I can whitelist it after giving 
the correspondent hard time for registering with the bums!  A 
fairly limited number of registrars fall into this category; I'd 
guess about ten or twenty at most--a manageable size for a 
blacklist.  Happily it costs about $50k to $100k, takes several 
months, and requires complete disclosure of one's identity to 
become a registrar.  It seems rather unlikely that throwaway 
registrars will ever develop as a problem.

I'm glad this works out for you. I personally receive mail from people all over 
the world (except maybe the usa, which only sends me spam), so this wouldn't 
quite work out for me I'm afraid.

Koen

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K.F.J. Martens, Sonologic, http://www.sonologic.nl/
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