Quickly Get a Router IP Address from the Command Line
If you need to quickly retrieve the IP address of the router you are connected to or through, you can find this information immediately in the Terminal of Mac OS X.
To uncover the connected routers IP address, just type the following at the command line:
netstat -rn |grep default
Hit return to see the results.
The result will look something like this, showing the router IP directly after “default”:
default 192.168.1.1 UGSc 108 0 en0
netstat will work for both wired and wireless connections, the difference of which will be shown as the interface. These are typically en0 and en1, though the port interfaces will vary slightly with Macs that don’t include ethernet ports or Wi-Fi / AirPort wireless card, and for Macs with only one form of network connectivity it will almost always be en0, though it varies per machine and per hardware.
For users who don’t want to bother with the command line, the router IP can also be found in Network preferences, and from the Wi-Fi menu in OS X, both of which are accessible from the graphical user interface and won’t require turning to the Terminal.
Thanks to Hans and Jen for the tip for an alternate way to the gateway retrieval from command line and to find it from the Network system preference panel. For those interested, the same netstat command also works in Linux, so you can extend your OS X knowledge beyond the Mac if you find yourself in a similar situation with another unix machine.