Address family
A classification for network address formats and protocol behavior. DDI work most often distinguishes IPv4 from IPv6.
Category glossary
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21 definitions associated with IP.
Address scope
The reachability domain of an address. IPv6 explicitly defines scopes such as interface-local, link-local, and global, while operational IPAM tools may also use scope to mean an administrative partition or DHCP range.
Dual stack
Operation of IPv4 and IPv6 on the same host, network, or service. Dual stack eases transition but requires parallel addressing, security, monitoring, and DDI policy.
Gateway
A router or next-hop system that connects a host's local subnet to other networks. DHCPv4 option 3 commonly distributes default router addresses.
Host address
An IP address assigned to an interface or node for unicast communication. In IPv4 subnet calculations, host addresses traditionally exclude the network and broadcast addresses.
ICMP
Internet Control Message Protocol, used for error reporting and network diagnostics. ICMPv6 also carries essential IPv6 functions including Neighbor Discovery and Router Advertisements.
Interface address
An IPv4 or IPv6 address configured on a network interface. A single interface can have multiple addresses, prefixes, scopes, and lifetimes.
IP address
A numeric identifier used by the Internet Protocol for routing and interface communication. IPv4 addresses are 32 bits and IPv6 addresses are 128 bits.
IPv4
Internet Protocol version 4, using 32-bit addresses and a variable header. Private addressing, NAT, broadcast behavior, and address scarcity strongly influence IPv4 DDI operations.
IPv6
Internet Protocol version 6, using 128-bit addresses, Neighbor Discovery, extension headers, and no broadcast. IPv6 addressing commonly combines Router Advertisements, SLAAC, DHCPv6, and prefix delegation.
Link
A communication domain on which nodes can exchange IP packets without an intervening router. DHCPv6 and Neighbor Discovery use link identity rather than IPv4-style broadcast domains.
Link-local address
An address valid only on the local link and not routed beyond it. IPv6 link-local unicast uses fe80::/10, while IPv4 link-local uses 169.254.0.0/16.
Loopback address
An address that routes traffic back to the local host. IPv4 uses 127.0.0.0/8 and IPv6 uses ::1/128.
Martian address
An address that is invalid or unexpected in a particular routing context, such as a loopback or private source arriving from the public Internet. The classification depends on interface, direction, and policy.
Multicast
Delivery from one sender to a group of interested receivers. IPv6 replaces IPv4 broadcast with multicast for many functions, and DHCPv6 clients use well-known multicast destinations to reach servers or relays.
NAT
Network Address Translation changes source or destination IP addresses, often also transport ports, as traffic crosses a boundary. NAT conserves IPv4 space but complicates end-to-end identity and address attribution.
On-link
Reachable directly on a local link without sending through a router. IPv6 hosts learn on-link prefixes from Router Advertisements and Neighbor Discovery rules.
Private address
An address intended for private networks rather than direct global routing. IPv4 private blocks are defined by RFC 1918, while IPv6 Unique Local Addresses use fc00::/7 with locally assigned space commonly from fd00::/8.
Source address
The IP address placed in a packet to identify its sender from the network perspective. It may differ from an application identity and can be translated or spoofed.
Special-purpose address
An address block reserved for a defined technical purpose rather than ordinary global unicast use, such as loopback, documentation, link-local, benchmarking, or NAT64 discovery. IANA maintains current registries.
Unicast
Delivery from one source to one destination address. Most ordinary host addresses are unicast, while anycast deliberately assigns the same unicast address to multiple nodes.