Getting the ip adress of the client in an Angular 2 - Meteor App

Hi,
I am a newbie and trying to get along with: https://www.angular-meteor.com/tutorials/socially/angular2/
How can I get the client IP address in a Angular 2-Meteor app. I saw this:
https://docs.meteor.com/api/connections.html#Meteor-onConnection

But I have no idea, where and how to call this method.
Thanks