IPv6

IPv6 (Internet Protocol version 6) is the successor to IPv4, developed to solve the address exhaustion problem inherent in 32-bit addressing. IPv6 uses 128-bit addresses, providing an address space of approximately 3.4 × 10^38 unique addresses — enough to assign public addresses to virtually every device on the planet.

Addresses are written as eight groups of four hexadecimal digits separated by colons, for example 2001:0db8:85a3:0000:0000:8a2e:0370:7334. The notation can be shortened by removing leading zeros in each group and collapsing one run of all-zero groups into ::, giving forms like 2001:db8::1.

IPv6 brings several practical advantages: a vastly larger address space, much less reliance on NAT, more efficient routing aggregation, improved multicast, and SLAAC for stateless address auto-configuration. The fixed-length header also enables faster processing in routers and aligns with modern network design.

IPv6 coexists with IPv4 through dual stack deployments, tunneling and translation mechanisms such as NAT64/DNS64. The internet is still in a long migration phase where most networks must support both protocols simultaneously.