AT&T SMTP Admin contact?

Michael Peddemors michael at
Tue Nov 24 22:01:31 UTC 2009

On November 24, 2009, Brad Laue wrote:
> True, but wouldn't a blacklist of SPF records for known spam issuing
>  domains be a more maintainable list than an IP block whitelist?
> (I'm no doubt missing something very obvious with this question)
> Brad

Yes, I think you are :)  First of all, domains are easier to throw away than 
IP Addresses, IP Lookups are more efficient than DNS SPF records, and SPF is 
not really meant to address Spam problems, although it can address some 

SPF works best to identify forgeries of large well known domains, but I think 
you do not really understand what SPF records do, or how they work.  Don't 
worry, many email operators don't either, and simply put in an SPF record that 
says that every IP can send email for that domain ;)

And think how large the theoretical database size would be for every domain, 
compared to the limited size of the IPv4 space..  But this is better taken off 
list you want to discuss SPF's usage in combatting spam.

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