> I am trying to ratelimit outgoing messages in my exim4 daemon. Many
> a times, our mail server has been hacked, multiple identity has been
> added and using those ids, hackers send out bulk spam mails. Once the
> limit is overcome, many domains are blacklisting us. As I understand
> from the manuals and searching the mailing lists, outgoing mails can
> not be ratelimited. Please correct me if I am wrong.
One hacky way around this is to run a second daemon in some way (there
are a bunch of ways; another (virtual) machine is the easy one). Route
outgoing messages to the second daemon via SMTP and then have that
daemon ratelimit how many incoming messages it accepts from your main
daemon.
If users submit outgoing mail to your daemon using SMTP, you can also
obviously ratelimit their incoming sending attempts. I don't think that
this works if users submit mail by directly running commands on the
same machine as the mailer, though, and it sounds like this may be your
problem.
- cks
