Re: [exim] Using GeoIP to block spammers - anyone?

On Fri, 2006-06-23 at 16:18 +0300, Odhiambo G. Washington wrote:

> | Your customers use this server for relaying? Then you probably identify
> | them by SMTP AUTH or fixed IPs. That should give you the facility to
> | block unauthorized senders.
>
> Yes and yes. I already do that. However, it has not stopped spammers
> from connecting to it, which is why I am looking at this other option.
>
> Kindly give me the idea in your mind, how I can block the spammers,
> without knowing their IP address before hand.

Even using a DNS blacklist the spammers will still connect to your
server. It will actually cause you more overhead as you'll have to do a
DNS check for each incoming connection.

If the spammers are just connecting and then being refused relay, after
they do not AUTH or originate from a know IP. Then you already are
consuming the least resources over any additional checks you can perform
within Exim.

They only way you could get less is to block the connections from ever
reach Exim. Like with a firewall. But that would require you to know
all the IP addresses that will ever be allowed to reach you machine to
white list them.