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

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Author: Odhiambo G. Washington
Date:  
To: exim-users
Subject: Re: [exim] Using GeoIP to block spammers - anyone?
* On 23/06/06 09:57 -0400, Chris Meadors wrote:
| 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.



I agree with you. Now tell me how much overheard this would add, if I
knew _all_ the IPs that are geographically in Kenya (via GeoIP):


check_connect:
    drop !hosts = cdb;/path/to/db/with/all_KE-IPs
accept



(or the reversing thereof, of this rule).




        cheers
       - wash 
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