addr_gen_mode

Configure the method for creating the IPv6 interface identifier of addresses for RFC4862 IPv6 Stateless Address Autoconfiguration and IPv6 Link Local.

The permitted values are: nm_setting_ip6_config_addr_gen_mode_eui64, nm_setting_ip6_config_addr_gen_mode_stable_privacy. nm_setting_ip6_config_addr_gen_mode_default_or_eui64 or nm_setting_ip6_config_addr_gen_mode_default.

If the property is set to "eui64", the addresses will be generated using the interface token derived from the hardware address. This makes the host part of the address constant, making it possible to track the host's presence when it changes networks. The address changes when the interface hardware is replaced. If a duplicate address is detected, there is no fallback to generate another address. When configured, the "ipv6.token" is used instead of the MAC address to generate addresses for stateless autoconfiguration.

If the property is set to "stable-privacy", the interface identifier is generated as specified by RFC7217. This works by hashing a host specific key (see NetworkManager(8) manual), the interface name, the connection's "connection.stable-id" property and the address prefix. This improves privacy by making it harder to use the address to track the host's presence as every prefix and network has a different identifier. Also, the address is stable when the network interface hardware is replaced.

The special values "default" and "default-or-eui64" will fallback to the global connection default as documented in the NetworkManager.conf(5) manual. If the global default is not specified, the fallback value is "stable-privacy" or "eui64", respectively.

For libnm, the property defaults to "default" since 1.40. Previously it used to default to "stable-privacy". On D-Bus, the absence of an addr-gen-mode setting equals "default". For keyfile plugin, the absence of the setting on disk means "default-or-eui64" so that the property doesn't change on upgrade from older versions.

Note that this setting is distinct from the Privacy Extensions as configured by "ip6-privacy" property and it does not affect the temporary addresses configured with this option.