If you want to find out where a given IP address is physically located on earth, there are quite a few online GeoIP lookup services you can try (e.g. geoiptool.com). These online services are mostly powered by freely available GeoIP databases such as those from MaxMind. Besides using such web-based services, there are different ways to query the GeoIP databases, notably via the Linux command line.

In this tutorial, I am going to describe how to geolocate an IP address from the command line in Linux.

Method One

The first method is to use geoiplookup tool which is a command-line client for MaxMind’s GeoIP databases. geoiplookup allows you to look up the geography or network information of an IP address (or hostname). You can install the tool (along with the free GeoIP database used by the tool) as follows.

To install geoiplookup on pcDuino Ubuntu :

$ sudo apt-get install geoip-bin

The default installation of geoiplookup comes with GeoIP.dat database file which is located in /usr/share/GeoIP. With this database, you can look up the country information only.

$ geoiplookup 23.66.166.151
GeoIP Country Edition: US, United States

You can download additional GeoIP databases from MaxMind, which give you more detailed information about IP addresses beyond country info. You can also download more up-to-date GeoIP.dat from the site. This is recommended because GeoIP.dat may have already been outdated by the time you install it from Linux repositories. The GeoIP databases available on MaxMind website are updated every month.

To install additional GeoIP databases from MaxMind, do the following. You may want to set up a monthly cronjob to automate this process.

$ wget http://geolite.maxmind.com/download/geoip/database/GeoLiteCountry/GeoIP.dat.gz
$ wget http://geolite.maxmind.com/download/geoip/database/GeoLiteCity.dat.gz
$ wget http://download.maxmind.com/download/geoip/database/asnum/GeoIPASNum.dat.gz
$ gunzip GeoIP.dat.gz
$ gunzip GeoIPASNum.dat.gz
$ gunzip GeoLiteCity.dat.gz
$ sudo cp GeoIP.dat GeoIPASNum.dat GeoLiteCity.dat /usr/share/GeoIP/

Now if you re-run geoiplookup, you will see the additional AS number information of an IP address. This basically tells you which administrative domain the IP address belongs to.

 $ geoiplookup 128.112.119.209

GeoIP Country Edition: US, United States
GeoIP ASNum Edition: AS88 Princeton University

When run without any parameter, geoiplookup tool automatically uses GeoIP.dat and GeoIPASNum.dat only, but not use GeoLiteCity.dat. The latter can give you city-level information.

To obtain city-level geolocation information, explicitly tell geoiplookup to use GeoLiteCity.dat database.

$ geoiplookup -f /usr/share/GeoIP/GeoLiteCity.dat 23.66.166.151

GeoIP City Edition, Rev 1: US, MA, Cambridge, 02142, 42.362598, -71.084297, 506, 617

The output includes state, city, zipcode, latitude and longitude. The accuracy of the inferred location varies across different countries and networks. For example, the geolocation result tends to be more accurate for broadband IP addresses, but not as accurate for mobile networks.
Method Two

If you want to avoid the hassle of installing and updating GeoIP databases, you can try ipinfo.io online service. Unlike other services, ipinfo.io provides JSON-based geolocation API, so you can easily look up geolocation from the command line, using tools like curl.

$ curl ipinfo.io/23.66.166.151 
{
  "ip": "23.66.166.151",
  "hostname": "a23-66-166-151.deploy.static.akamaitechnologies.com",
  "city": "Cambridge",
  "region": "Massachusetts",
  "country": "US",
  "loc": "42.3626,-71.0843",
  "org": "AS16625 Akamai Technologies European AS",
  "postal": "02142"
}

Note that the access to their API is rate-limited at 1,000 API requests per day.