Maybe some here know of this and maybe not, but I figured that I would share and possibly help others.
Long ago, I used to do blacklisting by netblocks, which was a tedious process, creating very large lists in my firewall config.
I just came across a nice set of RBL's today which allow for blocking by country of origin.
Info here: http://countries.nerd.dk/
Only had it implemented on my Astaro for a couple of hours now. Starting with the worst offenders for today, China, Thailand, Russia, and the Koreas. The entries were added to Email Security>SMTP>Anti-Spam Tab>RBLs>Extra RBL Zones.
So far, with these 5 zones added, the difference in CPU and RAM usage on my Astaro is negligable, and after 2 hours I've got 0 spam in my quarentine manager when usually there would be several hundred. This is a huge time saver for me, since the ability to set a blackhole threshold for spam assassin was removed for V7. I fully expect to have to add a few more zones over time as different countries are the "source du jour".
Makes me wish Astaro had a Realtime WhiteList option. I could then just pop in the RBLs for the few countries we do business with and everything else would be blocked.
My sole concern with this RBL (which holds true for most of them), is that it's maintained by "some guy" and at some point down the road he may decide that he's bored with the whole thing and pull the plug.
Since Astaro V7, does it's own Geolocation lookup anyway (as displayed in the top spam countries table under Email Security), this form of spam mitigation could be an extremely effective and low overhead technique for Astaro to implement natively.
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