Get public (remote) IP address

Question

I was wondering if there was a simple way to get the public IP address of a computer using Ruby.

Answer 1

Akamai provides a "What is my IP" page that you can fetch:

require 'open-uri' remote_ip = open('http://whatismyip.akamai.com').read 

There are a few alternatives that do the same thing, though:

• http://whatismyip.akamai.com
• http://ipecho.net/plain
• http://icanhazip.com
• http://ident.me
• http://bot.whatismyipaddress.com

You can also use the ipv4 and ipv6 subdomains with icanhazip.com.

If you don't want to depend on a third party, you can roll your own in a one-line rack app and deploy this for free on Heroku or whatever. It takes into account that X-Forwarded-For may contain a comma separated list of proxy IP addresses and only returns the client IP.

# config.ru  run lambda { |env|   remote_ip = env['HTTP_X_FORWARDED_FOR'] || env['REMOTE_ADDR']   remote_ip = remote_ip.scan(/[\d.]+/).first   [200, {'Content-Type'=>'text/plain'}, [remote_ip]]  }