At 10:00 AM -0400 2002/08/21, sjj@pobox.com wrote:
I'd like to be able to publish DNS records announcing my domain's *outbound* mail servers, with nice abbreviated forms to say "they're the same as my inbound (MX) records" or "any IP in x.y.z/24". Then cooperative ISPs (like say America Online) could refuse any email from my domain that originated from some random cable modem, instead of accepting it and then flooding me with 20000 bounce messages.
Doesn't work. Back when I was working at AOL, every three or four months some new VP would come up with the "bright" idea that we should not accept mail from an AOL e-mail address that does not come from our own servers. The answer is the same -- doesn't work. The reason is that there are these things called mailing lists. Any user from any site in the world (including AOL) could post to the list, and then there would be e-mail claiming to be from an AOL user which is addressed to other AOL users, but which does not come from the AOL servers. Now, I'm sure that the next thing you're going to tell me is that we'd be talking about envelope sender addresses, not the "From:" address. Well, many people run mailing lists as simple aliases, as opposed to using "real" mailing list management software. I'll say it again -- doesn't work. -- Brad Knowles, <brad.knowles@skynet.be> "They that can give up essential liberty to obtain a little temporary safety deserve neither liberty nor safety." -Benjamin Franklin, Historical Review of Pennsylvania. GCS/IT d+(-) s:+(++)>: a C++(+++)$ UMBSHI++++$ P+>++ L+ !E W+++(--) N+ !w--- O- M++ V PS++(+++) PE- Y+(++) PGP>+++ t+(+++) 5++(+++) X++(+++) R+(+++) tv+(+++) b+(++++) DI+(++++) D+(++) G+(++++) e++>++++ h--- r---(+++)* z(+++)