How accurate are GeoIP tools?
 

I want to start sending all my crap countries somewhere but I don't want to accidentally send some good traffic too. Do these things ever list a visitor as China when they're really United States or something? Or are they 95%+ accurate to the country at least?

I guess people using a proxy will show up at a different country, maybe that would be the biggest problem?

they're generally pretty accurate, but if an IP block gets transferred to a new ISP it can take a while to update sometimes.

usually 99+% accurate but that's 100 users that are wrong for every 10k...

I think they would be good country by country.

I live in Northern California, and my internet comes out in Southern California. I noticed a while back we were seeing ads for stuff down in SoCal a lot. Then it hit me.

Depends what's more worse:

a) The chance of a user from a "good" country being redirected
b) The chance of a user from a "bad" country seeing your good content

If it's scenario (a) then using browser language rather than (or in addition to) geoIP may help you reduce the chances of a false positive.

Interesting, would that really be more reliable? Do browsers ever block that info or fail to pass it along?

Maxmind GeoIP is 99.8% accurate according to them...
their free version accuracy is only 99.5%

http://www.maxmind.com/app/geolitecountry
look at the bottom of the page...

Just go with Maxmind GeopIP, it's by far the best solution.

The browser langue doesn't say anything. For example everyone in the Philippines uses English browsers.

Most of the billers use Maxmind as well, so even if they are 'wrong' for a certain user, he would most likely be declined at the processor anyway for being from a 'bad' country.

I just block shit traffic on some of our servers now. Nobody wants it and those that do have nefarious uses for it.

Maxmind GeopIP is quite nice solutions for redirect crapy traffic and 97% on free version is really enough to do this

Maxmind's free GeoIP database is pretty good, but from testing, definitely not 100% accurate. The paid database seems to be quite a bit more accurate, moreso than what their website advertises, especially if you're targeting people on a city level as well.

They are accurate detecting countries most of the time, but they suck at detecting exact city.