Kelson wrote:
Matt Kettler wrote:
That said, some folks still hate it because you're using some (very
little) of their CPU and network to handle your spam.

Also, a large number of verifications (say, because someone has been sending lots of spam with forged headers) looks suspiciously like a dictionary attack.


Exactly. In effect what sender verification does is cause your server to perform the dictionary attack instead of the spammer.

Say im a spammer. I send messages to [EMAIL PROTECTED], [EMAIL PROTECTED], [EMAIL PROTECTED], etc and see which ones are accepted to gather valid addresses.

With sender verfication, spammer now sends messages to [EMAIL PROTECTED] with a return address of [EMAIL PROTECTED], [EMAIL PROTECTED], etc. Your server does the sender check to see if [EMAIL PROTECTED] exists. Your server is doing the work for the spammer now and looks exactly like a dictionary attack. This could (and does) very easily get you onto several blacklists.

Sender verification?  Not for me, thanks.

-Jim

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