Backscatter increase clogs inboxes [LWN.net]

Backscatter increase clogs inboxes

Posted Apr 10, 2008 4:49 UTC (Thu) by zlynx (subscriber, #2285)
In reply to: Backscatter increase clogs inboxes by dlang
Parent article: Backscatter increase clogs inboxes

In the early days of SPF some sites were configured to give bonus points or whitelist source
domains with SPF.

The right way to use SPF is negative scoring only.  If email doesn't match its domain SPF then
give it spam points ... whatever you happen to think it's worth.

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what is SPF good for ?

Posted Apr 10, 2008 16:50 UTC (Thu) by copsewood (subscriber, #199) [Link]

Personally, having implemented it and then given up, I think the only useful application for
SPF is whitelisting. If you score based on SPF pass or fail and this increases your false
positives/negatives there is no point using it in this way, unless your objective is to punish
people for incorrect or unmaintained SPF setups. However, if you have whitelisted the domain
as having a well-managed mail system then SPF can give you some confidence a message from a
particular IP address is from that domain.

what is SPF good for ?

Posted Apr 10, 2008 17:10 UTC (Thu) by zlynx (subscriber, #2285) [Link]

That's another good use of it.  I don't whitelist at the mail server level so I didn't think
of it.

As for punishing people with bad setups.  Yes!

Admins are already punished for running open relays, not having reverse DNS records, firewall
blocking their sending SMTP servers and many other things.  If they publish a SPF record, it
had better be correct.

what is SPF good for ?

Posted Apr 11, 2008 15:53 UTC (Fri) by giraffedata (subscriber, #1954) [Link]

"As for punishing people with bad setups. Yes!"

If only there were some way to do that without punishing the sender and recipient of the mail more.

I have often seen instances of mail recipients rejecting my mail out of spite, based on an opinion of how the mail system should work. In every instance, the recipient would have enjoyed receiving my mail more than I would have enjoyed him receiving it. In most cases, it was a reply to an email he sent me.