Talk-Polywell.org

Where can I find an up-to-date mapping of countries to IP address blocks?
There are some hooligan states that I want to permanently ban from my inbox.

I use MaxMind at work.

Thanks.

You could also use arin.net for that, thought it may be more work. ARIN is the parent body for IP allocation.

Yeah, you can use ARIN, but you have to process the extracts yourself, and accumulate the records into a usable format. It's easy, but I don't know your comfort level with such things. If you're interested, you can find the latest files for all the registries here. Each registry has its own subdirectory. A description of the format can be found in the README file.

The main reason I use MaxMind is they offer apis in several languages to work with their database so you can just give it an IP and it spits out a country.