DNSBL support

[tlk]

I forked the stable branch and have added basic support for DNSBL as an alternative to the static GeoIP database file. See http://countries.nerd.dk and http://noc.bit.nl/dnsbl/ascc/ for details on DNS based ip-to-country mapping services. Let me know if you are interested in this.

[wedi]

Hi Thomas, I am interested. Pushing the plugin fully functional to the users without them needing to download or setup anything except the countries sounds very appealing to me. Unfortunately I’ll be afk for some time as I had a skiing accident but as soon as I recover I’ll be more than happy to include your code (with the option to return to the GeoIP database used so far).

[tlk]

Hi Dirk I'm sorry to hear about your accident --- hope you'll recover soon!

I'm currently using the dnsbl-fork in a single wordpress installation and consider it a working proof of concept, but I haven't tested critical scenarios such as what happens when the DNSBL name server:

• cannot be reached (temporary network outage between web server and name server)
• doesn't respond properly (temporary malfunction at name server)
• cease operations (long term concern)

I suggest two fallback strategies:

• allow access from all ip addresses (default)
• reject access from all ip addresses, but do allow access from a set of known ip addresses which must be provided when choosing this strategy.

I believe that the current dnsbl-fork simply rejects all ip addresses in case of failure.

[tlk]

The bruteforcelogin.bl.blocklist.de service from http://www.blocklist.de/en/rbldns.html is also interesting.