Networking · Fundamentals
IPv6
The 128 bit successor to IPv4, with vastly larger address space, mandatory multicast based neighbour discovery and no need for NAT.
IntermediateUpdated 2026-09-01
Overview
IPv6 replaces ARP with Neighbor Discovery, broadcast with multicast, and DHCP only addressing with a choice of SLAAC, DHCPv6 or both. A /64 is the standard subnet size regardless of host count.
Most enterprises run dual stack. The operational risk is unmanaged IPv6: hosts often prefer IPv6 by default, so an unmonitored, unfiltered IPv6 path can bypass IPv4 only controls entirely.
Security considerations
- Apply equivalent firewall, logging and detection policy to IPv6, or disable it deliberately at the interface level.
- Enable RA Guard to prevent rogue router advertisements.