Difference Between Public and Private IP Addresses
In order to access the internet, your computer needs a public IP address usually assigned to you by your ISP. Nowadays, your router or gateway will allow computers on your network to share that one public IP address. To do this, though, each computer still needs its own, private address - and your router will have one too. This private IP address doesn’t need to be globally unique since it is not a direct access address, that is, no one can access the IP address 192.168.0.1 outside of a private network.
Private IPs
Among these addresses, the IANA reserved certain number blocks to be private. These are:
10.0.0.0 - 10.255.255.255172.16.0.0 - 172.31.255.255192.168.0.0 - 192.168.255.255
These private IPs total about 17.9 million different addresses, all reserved for use on private networks. This is why a router’s private IP does not need to be unique. The router assigns a private IP address to each device in its network, whether it’s a small home network or an enterprise-level organization. Each device inside the network can connect to another device in the network using this private IP. Private IP addresses cannot, however, access the internet. Private IP addresses need to connect through an ISP, for example, Comcast, AT&T, or Spectrum. In this way, all devices connect to the internet indirectly, first connecting to a network (that is connected to the internet), then connecting to the larger internet. If you want to connect to the internet, you must first leave your network—that’s done through a gateway device such as your router. So your computer will need to know the address of the router (maybe 192.168.0.1) to send it anything that you want to go ’long-distance’ so to speak. The router then connects to your ISP which connects you to the broader internet, and your message is routed to its recipient. The route looks something like this, assuming the presence of a router on each end:
Public IPs and the IPv6 Standard
Public IP addresses must be globally unique. This posed a problem for the IPv4 standard since it can accommodate only 4 billion addresses. Hence, IANA (IANA is the Internet Assigned Numbers Authority, so they are responsible for all numbers on the internet, IP address included) introduced the IPv6 standard, which supports more combinations. Instead of using a binary system, it uses a hexadecimal system. An IPv6 address is composed of eight groups of hexadecimal numbers, each comprised of four digits, for example, 2001:0db8:85a3:0000:0000:8a2e:0370:7334. This system can accommodate almost infinite growth in IP addresses, up to 340 undecillion (a number with 36 zeros). No matter what, the basic structure of an IPv6 address will be as such:
Hexadecimal characters (0123456789abcdef)32 characters8 sections (words or hextets) of 4 characters eachWords separated by a colon (e.g. abcd:1234 )
Find Your IP Address
There are multiple ways to find your IP address. If a computer (or another connected device) operates on a private network that connects to the internet (like those in most homes), the modem must have a private IP address, but devices connect to the modem may all share an an IP assigned by the router and a public IP address. You rarely need to know the public address, unless you’re troubleshooting your computer remotely and need to connect to it.
Find Your Public IP Address
The easiest way to locate your public IP address is to navigate to google.com and enter my IP in the search box. Google returns your public IP address. There are other ways, including websites specifically dedicated to returning a public IP address such as whatsmyip.org or whatIsMyAddress.com.
Find Your Private IP Address
Here’s how to find your private IP address:
Change Your Router’s IP Address
Your router’s IP address is set by the manufacturer at the factory, but you can change it at any time using the network router administrative console. For example, if another device on your network has the same IP address, you could experience an address conflict so you would want to ensure that you have no duplicates. To access the router administrative console, enter its IP into a browser address bar, for example, http://192.168.0.1. Any brand of router, or any computer on a local network, can be set to use this address or a comparable private IPv4 address. As with any IP address, only one device on the network should use 192.168.0.1 to avoid address conflicts.
