Private - Public IP Addresses

IP addresses (Internet Protocol Addresses) are assigned to every device that is connected to a computer network. They are numeric 'locations' for devices that is used to send data to specific devices.

Private IP addresses are usable only within the network they exist in. They are typically class C addresses, such as 192.168.x.x. These addresses are assigned to specific devices on a network, and the router routes traffic to it (if applicable). Most often, these addresses are assigned by the router using DHCP and an address can only be used with one device. Private IP Addresses are non-routable.

Public IP addresses are assigned by an ISP (typically) and apply to an entire LAN. This is the address that other devices on the internet see and communicate with. Data is transferred to specific devices from the Internet using NAT and port forwarding. NAT occurs 'automatically' while ports can be denoted with a colon after the IP address (e.g. 255.255.255.255:99999). Puplic addresses are routable.

Currently, IPv4 is the standard but IPv6 is becoming more common.

https://www.youtube.com/watch?v=EOhBzhs0ACU&index=10&list=PLCiOXwirraUCw0BWhWk_5rInOWRnzf8Xm