You are likely aware that an IP address is a number in the format aaa.bbb.ccc.ddd. It is this IP address that devices use to communicate with other devices over the Internet. Thus, public IP addresses are those permanent/unique IP addresses allocated to Internet-connected devices and can be routed over the Internet independently. They serve as permanent addresses for Internet-connected devices, just like your permanent residential address.
When you type www.gmail.com (or) www.msn.com, a DNS server converts the name into an IP address, which is then used to identify the servers that host those websites. These websites are assigned a permanent IP address, referred to as a Public IP address. You can access these websites by their public IP address or domain name. Not every website needs its own public IP address.
All IPv4 addresses can be broken down into two categories: public addresses (also known as "WAN addresses"), which are used on the Internet, and private addresses, which are used on a local network (LAN).
A public IP address is one that is used to access the Internet. In contrast to private IP addresses, public IP addresses can be routed over the Internet. Having a public IP address on your router enables you to set up your own server, access your computer remotely, and monitor your surveillance cameras from anywhere within the global network.
Every public IP address on the Internet is unique to its host or server and cannot be duplicated. An ISP can provide home users with one or more public IP addresses (usually a paid service).
Your internet service provider assigns your router a public IP address that is visible to the public. Your router connects to the Internet using its public IP address. Computers on the Internet can communicate with your network devices using your public IP address.
You can't go online without a public IP address that identifies your device on the Internet. In a typical home network, the router acts as a gateway between your computer and the Internet, managing all connections on behalf of your network's devices.
When a user connects to the Internet, his computer is typically issued an address from a pool reserved by the Internet Service Provider (ISP) for its customers. When he enters a website address, such as google.com, the website name is converted into the IP address of the website's hosting server. The server utilizes the computer's public IP address to determine where to send the requested web page.
Most enterprise networks use both public and private IP addresses. The Enterprise Teleworker, Branch, and Campus modules all employ private IP addresses. The following modules feature public addresses: