I would like to get the user IP address in my meteor application, on the server side, so that I can log the IP address with a bunch of things (for example: non-registered us
This answer https://stackoverflow.com/a/22657421/2845061 already does a good job on showing how to get the client IP address.
I just want to note that if your app is served behind proxy servers (usually happens), you will need to set the HTTP_FORWARDED_COUNT environment variable to the number of proxies you are using.
Ref: https://docs.meteor.com/api/connections.html#Meteor-onConnection