[exim] Fighting DEA providers

Hi All,

We have a subscription service where users can sign up and receive
free access, prior to having to subscribe. Allot of users, are
signing up with DEA based email addresses, thus gaining access and
more than a single free trial - which is far from ideal for us.

Is there any specific MTA way of dealing with DAE providers? For one,
that I have thought about, is that I can inject email into Exim using
a specific router. Is there a way to tell the router to queue the
mail for a random period of time prior to delivering it? Most DAE
addresses will for example only be active for a short period of time,
thus using a delay, can cause the email to bounce.

Is there perhaps any other, better, more intelligent ways of dealing
with DAE? A RBL of sorts? We have a database of some 400 odd domains
currently, and it's growing nicely but I'd prefer to be pro-active
about this and block before we have to 'manually' add it to a
database.

Thanks,


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Regards,
Chris Knipe