IPv6

Address Structure and Notation

IPv6 uses 128-bit addresses, expressed as eight groups of four hexadecimal digits separated by colons: 2001:0db8:85a3:0000:0000:8a2e:0370:7334. Two compression rules simplify notation: consecutive all-zero groups collapse to :: (used once per address), and leading zeros within each group are omitted. The example above becomes 2001:db8:85a3::8a2e:370:7334.

The address space — 2^128 approximately 3.4 x 10^38 — is designed so that every device on earth could have billions of globally routable addresses, eliminating the need for NATNetwork Address Translation. A method of remapping private IP addresses to a single public IP address (and vice versa) at a router, allowing multiple devices to share one public IP. A key technique for mitigating IPv4 address exhaustion..

Address Types

IPv6 replaces BroadcastA network communication method that sends data to all devices on a subnet simultaneously. The broadcast address is the last address in a subnet, such as 192.168.1.255 for a /24 network. with targeted communication. Link-local addresses (fe80::/10) are automatically assigned to every interface and are used for neighbor discovery within a segment. Global unicast addresses (2000::/3) are globally routable, equivalent to Public IP AddressA globally unique IP address assigned by an ISP that is routable on the public internet. Every device directly accessible from the internet must have a public IP address. in IPv4. Unique-local addresses (fc00::/7) resemble Private IP AddressAn IP address from reserved ranges (10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16) used within local networks. Private addresses are not routable on the public internet and require NAT for external communication. — routable within an organization but not on the public internet.

Solicited-node multicast replaces ARP: each host joins a multicast group derived from its address, and neighbor discovery queries target only that group rather than broadcasting to all hosts.

Stateless Address Autoconfiguration (SLAAC)

IPv6 devices can configure themselves without DHCPDynamic Host Configuration Protocol. A network protocol that automatically assigns IP addresses, subnet masks, gateways, and DNS servers to devices when they join a network. using SLAAC. A router sends periodic Router Advertisements containing the network prefix; the host appends a locally generated interface identifier (often derived from its MAC address via EUI-64, or randomly generated for privacy). The result is a complete, globally routable address with no manual configuration.

Use IP Lookup to analyze IPv6 addresses, and DNS Lookup to verify AAAA RecordA DNS record that maps a domain name to an IPv6 address. Named "AAAA" (quad-A) because an IPv6 address is four times the size of an IPv4 address. mappings for a domain.