Hello,
We run a free accounts mail server (like gmail) and we struggle with the
outgoing spam problem.
Spammers abuse our service by creating accounts and then sending out spam.
It is very easy and free to create an account and we want it to stay that
way so blocking or removing spammers accounts is not a solition - they can
easily create many new accounts.
They use tens of different IP addresses and send from different locations
and countries so per IP limits really don't work.
Many of their IPs aren't listed on any RBL at all.
I feel it would be hard to filter them by message contents - they avoid
patterns by changing headers (even an encoding), message texts or links if
they add any.
How can we fight this?
How other free mail service providers block this?
Best regards
--
Marcin Szymonik
szymoni...@gmail.com
