October 10, 2009
How To: Check your computer’s IP address
An IP address is a number that identifies devices connected to a network. In short every single computer, mobile phone, printer, server, etc, connected to the Internet is assigned a unique address. Note that this is totally different then a MAC address which is unique and is only assigned to one device. IP address can and do overlap within certain boundaries.
As is usual in the IT world, reality is of course far more complicated then that. Since there are more devices then IP addresses these days, proxy servers, routers, Gateways and DHCP are all technologies and services that help increase the number of IP addresses by reusing numbers out of three different common publicly available sets of number ranges. These number ranges are:
10.0.0.0 – 10.255.255.255
172.16.0.0 – 172.31.255.255
192.168.0.0 – 192.168.255.255
Note that there is one more special IP address 127.0.0.1 which is known as the Loopback or Localhost IP address. Other then troubleshooting there is few reasons to use this address.
Most desktop computers will have IP address assigned from one of these three sets of numbers. But, through a bit of network magic on the ISP side, the number seen by other computers on the Internet may be totally different. Luckily, your publicly viewable IP address can be found extremely easy by a multitude of free Web-Based Services. What is my IP being one of the easiest to remember.
But on a local network, knowing the IP address of each device could be critical. Especially when attempting to connect for file sharing or screen sharing reasons.
WindowsAll versions
The quickest way to find the IP address on all version of Windows (and even DOS!) is to open a command line window. This is frequently done by clicking on Start, going to Run, typing in cmd and then clicking enter. This should open a command line window. In this window simply type ipconfig and hit enter again.
The line that says “IP Address” contains the information we need!
Unix (Linux, BSD, OS X)
Open a terminal window. Step by step directions will vary by OS, but if you’re in a GUI look for a terminal icon. If you’re not in a GUI, just type the below command.
ifconfig -a
While hard to read, this does give a lot of information. The line to look for is “inet” this tells the currently assigned IP address of each individual network adapter in the computer. If the active network jack is not known, it may take some trial and error to find the right IP address. Note that depending on the version of Unix, which driver is loaded and what network devices are being used this screen can look extremely different.
Mac OS X
In addition to the command line terminal option above, there is a way to find OS X’s IP address through the GUI too. Click on the Apple Icon in the upper right hand of the screen. Go down to “System Preferences” and click. Look for the Network Icon, usually under “Internet & Wireless” and click on it.
Right under the “Status: Connected” line is the IP address. By clicking on the different network devices on the left side, each individual IP address can be found.
At this point we should have all the information we need no matter which operating system is being used!
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