IPv4 vs IPv6

IPv4 addresses are 32 bits long and written as four decimal numbers separated by dots, such as 203.0.113.5, allowing about 4.3 billion addresses. That pool has effectively run out, which is why techniques such as NAT let many devices share one public address.

IPv6 addresses are 128 bits long and written as eight groups of hexadecimal digits separated by colons, such as 2001:0db8:0000:0000:0000:ff00:0042:8329 (shortened to 2001:db8::ff00:42:8329). IPv6 provides an almost unlimited number of addresses, simpler routing and built-in support for auto-configuration.