Quantcast Top 10k5,356 of 10,000
Quantcast Top 100k45,928 of 100,000
BuiltWith Top Million344,016 of 939,844
Entire Internet48,523,513 of 370,383,747
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The Sender Policy Framework is an open standard specifying a technical method to prevent sender address forgery.
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We know of 48,523,513 live websites using SPF in our records.
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