question on ptr rr

Sun Feb 8 20:29:17 UTC 2004

sean at donelan.com (Sean Donelan) writes:

> A Google search turned up http://www.unixwiz.net/techtips/pacbell-rdns.html
> 
> But wouldn't this defeat the very behavior you are depending on to
> block mail?  If every network administrator had reverse DNS for every
> IP address, your check for systems lacking rDNS wouldn't work.

that's one check of many.  the PTR has to match the HELO, which means all
of the worms and spammers who forge @yahoo.com addresses and use YAHOO.COM
as their HELO will continue to get hammered.

> Or do we actually want a Fortune 1000 network.  Direct communications
> are prohibited between most users.  If you are not a Fortune 1000 network,
> you must forward your email through an approved provider which will check
> the mail for unauthorized content.

yes, actually, that's what we're headed for.

> Suppose AOL, MNN, Yahoo, etc agree to accept mail from each other and not
> from other people.  This is pretty much how the world worked from
> 1980-1990.  CompuServe, MCIMail, The Source, Delphi, etc.

fine by me.  the people i want to exchange mail with aren't AOL users anyway.
-- 
Paul Vixie