Mail alert

Question

I was thinking of creating a poster-like service where users can send messages to a fixed address, such as [e-mail] , and then message authentication will be based on some combination of address and header. Posterous seems to be doing something smart so they can detect that the message is being tricked or sent from an unknown source.

Does anyone know what they can do?

Answer 1

There are a few basic heuristics you could use to try and discover it.

- , . SPF, , IP- . - , , , , . .

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- ( ), , , .

, / , ( ..). ).