Quantcast Top 10k5,453 of 10,000
Quantcast Top 100k46,446 of 100,000
BuiltWith Top Million345,038 of 942,376
Entire Internet41,480,275 of 370,393,936
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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 41,480,275 live websites using SPF in our records.
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