nanog mailing list archives

Re: misunderstanding scale, SMTP edition


From: Tony Finch <dot () dotat at>
Date: Wed, 26 Mar 2014 17:36:38 +0000

John Levine <johnl () iecc com> wrote:

If I were a spammer or an ESP who wanted to listwash, I could easily use
a different IP addres for every single message I sent.

Until mail servers start rate-limiting the number of different addresses
that are used :-) You can do something like the following in Exim, which
limits IPv6 senders to 16 addresses per /64 per day.

  defer
    hosts = <; 2000::/4
    ratelimit = 16 / 1d / per_conn /\
      unique=$sender_host_address /\
      ${mask:$sender_host_address/64}

Tony.
-- 
f.anthony.n.finch  <dot () dotat at>  http://dotat.at/
Shannon, Rockall: Southerly 5 or 6 at first in west, otherwise variable 3 or
4, becoming northeasterly 4 or 5. Moderate or rough. Showers. Good,
occasionally moderate.


Current thread: