How-To Block Spam Using Reverse DNS Lookup
Published on February 14, 2007
Spammers use fake “From” addresses in the spam they send. Forging the “From”" field give spammers anonymity along with something else they crave:
Spammers do not want emails bounced back to them!
Forged Email
When a spam message does not have a valid address (eg: unknown@yvod.com), that message is supposed to be returned (bounced) to the sender notifying them that the message was undeliverable.
However, if the sender “From” address is forged, the message will be bounced to the forged email address allowing the spammer gets away clean. Unfortunately, the person who had their email forged gets all the non-delivered junk. Yuck!
Reverse DNS Lookup
As a means of avoiding this behavior YVOD has installed a Reverse DNS Lookup filter for all email to stop spam
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