nanog mailing list archives

Re: AW: SPF Configurations


From: "John R. Levine" <johnl () iecc com>
Date: 4 Dec 2009 19:54:11 -0500

Right.  The only major mail system that pays attention to SPF is
Hotmail, but there are enough small poorly run MTAs that use it that
an SPF record which lists your outbounds and ~all (not -all) can be
marginally useful to avoid bogus rejections of your mail.

For example :
[ various large ISPs that publish SPF ]

Perhaps this is a language problem.  In English, "publishes" is not a
synonym for "pays attention to."  As I said, you need to publish SPF
to get mail into Hotmail.  That's why people do it.

I know there is a problem so far with forwarded emails but there is  also a
solution :
[ hoary SRS proposal to change every SMTP server in the world to make them
match what SPF does ]

Sigh.

Every time a mail arrives that is an SRS address the password and timestamp
could be checked, and faked or outdated recipients could be rejected.

You might want to look at BATV, which has nothing to do with SPF, but
I have found is quite useful for recognizing spam blowback.

R's,
John

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