BCP38 making it work, solving problems

Edward B. Dreger eddy+public+spam at noc.everquick.net
Mon Oct 11 18:12:45 UTC 2004

RB> Date: Sun, 10 Oct 2004 20:14:01 -0700
RB> From: Randy Bush

RB> when it solves critical problems, it'll grow more quickly.


* Use 25/TCP for SMTP and 587/TCP for submission
* Block outbound SMTP by default, but allow for the clueful
* Run SMTP authentication
* Let each authenticated user have whitelisted sender addresses
  that they can use
* Limit whitelist size
* Add a delay and/or rate limit to whitelist additions.

Not perfect, and certainly subject to social engineering and
possible automated attack on the whitelist mechanism, but it
should decrease the number of cable/DSL pipes filled with forged
mail transmissions.

This isn't the first time I've suggested it, and I'm sure others
have, too.  Not once have I received a response to the extent of
"I'd love to implement this if it existed".  People are worried
about OPNs, not their own networks.  IMNSHO, worrying about N-1
ASNs scales far more poorly than worrying about one ASN.

Of course, note the parallel to BCP38; I'm sure someone will be
quick to point out that, unless adopted universally, forged mail
will still exist.  Enter SPF as a bandaid on the receiving side,
and rehash that discussion.  Combine with BMF, DNSBLs, and one is
well on the way to much cleaner mail.

Has anyone on NANOG ever solved a jigsaw puzzle with 500+ pieces?
Or are "age 2 to 4" puzzles too difficult, as even they tend to
have around ten pieces per puzzle?

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