Outbound IP Adresses
Pretty handy API call that returns the senders outbound IP Address, might seem like a basic thing but very useful when you need it!! Recently used it to confirm the external IP of a NAT Gateway so we knew what to allow through the firewall.
http://api.ipify.org/ (opens in a new tab)
It is just an API call so it can be run from a terminal, browser, insomnia......whatever really.