sean@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