router's ip

hi guys, how can i check my router's ip address? i know about ipconfig for local machine, but how about router?

lot of the routers ip adress are 192.168.1.1 or 192.168.0.1. most of the routers have a browser interface and simply put in one of the ip addresses up above and it will show the interface where you can change the setup of the browser. the other wway is to open up your network proberties and then support tab and the default gateway is the routers ip address

i believe that is the router's internal ip address right? how about external?