Re: [nznog] New Spam Killing Technique

I think you might have it around the wrong way. If you were connecting via xtra, and were trying to use telstraclear's smtp server it would fail using this approach, but if memory serves me correctly you can't do this now anyway ( I could be wrong). from the faq: How does it work? Suppose a spammer forges a hotmail.com address and tries to spam you. He connects from an IP address somewhere. When he declares MAIL FROM: , you don't have to believe him. You can ask Hotmail if the IP address comes from their network. (In this example) Hotmail publishes an SPF record. That record tells you how to find out if the client IP address belongs to them. hotmail.com IN TXT "v=spf1 ptr -all" You execute the "ptr" mechanism, which means: find out the hostname of the client; if it ends in hotmail.com, it's legit. If the message fails SPF tests, it's a forgery. That's how you can tell it's probably a spammer. jamie On Sat, 2004-01-24 at 23:11, Barry Murphy wrote:

I don't see how this would work.

Lets say I connect to xtra as my ISP, however I have a clear.net.nz email address and use xtra's smtp server to send my email. This sort of system would block it as being spam because it wouldn't be going through the correct poviders smtp server. One alternative would be to allow pop to smtp auth, but I don't see large providers doing such a thing.

Barry

----- Original Message ----- From: "Jamie Baddeley"

...

http://www.nwfusion.com/news/2004/0122aoltest.html?net

http://spf.pobox.com/

worth looking at....

jamie