ip2c (ip to country) is a program written to determine the country associated to a specific IP address.
The program queries the five main whois servers responsible for each region of the world and try to automatically establish the most authoritative for the IP specified. Then it return the country's two-letter TLD (for example US), the extended country name (for example United States of America), its world region (for example North America) and a string containing a brief description of the organization managing the block of IP addresses containing the submitted IP (when available).
The program can also process a list of IPs stored in a comma delimited file and generate a new file with the country fields added to it.
ip2c is a multithreaded application, and queries all the servers in parallel to minimize the overall response time.
ip2c is distributed as a console (or command line) application (ip2c.exe) and a Windows GUI application (ip2c_gui.exe).
The features of the two versions are somewhat different and examined in more detail in the help file.
As usual I wrote the program for my specific needs, but you are welcome to use it if you find it useful.
PLEASE READ THIS:
This program is not a substitute for the offline databases offered by many geolocation commercial services if you need to process huge amounts of data.
Remember a whois server always has some kind of acceptable usage policy you should be familiar with.
If you use this program to manually check some IP addresses from time to time obviously there is no problem, that is what they are there for.
But if you use the batch mode you must NOT abuse the server. It's a service for all the Internet community so try to be polite.
Use the available program's options to limit the frequency of your queries and don't try to process a thousand of IP addresses in a single shot.
If you commit abuse you can be slowed down, banned for 24 hours, or permanently.
If you are in doubt look online for the policies of each whois server or ask to its admin directly.