IPv6 Privacy Extensions (Temporary Address)
IPv6 Privacy Extensions generate a randomized, temporary interface identifier instead of one derived from a device's MAC address, so the same device looks different on every network and over time. AdminKit's guide on MAC address randomization explains why this replaces the older EUI-64 approach for most traffic today.
By AdminKit team, Netbase JSC · Updated
IPv6 Privacy Extensions, defined in RFC 8981, let a host generate a temporary IPv6 address with a randomized interface identifier alongside its normal address, instead of deriving that identifier deterministically from the device’s MAC address the way EUI-64 does. RFC 8981 obsoletes the original specification, RFC 4941, published in 2007, but keeps the same underlying goal: an EUI-64-derived address embeds a stable, globally unique hardware identifier that lets a device be correlated across different networks and over time, purely from its address. A temporary address changes on a regular schedule and per network, breaking that correlation for outbound connections while a device’s stable address still handles incoming connections to any services it runs. Modern operating systems enable temporary addressing by default for general traffic, reserving the deterministic address mainly for cases that need a stable, reachable endpoint.