ipv6: NetworkManager Reference Manual

## ipv6 ipv6 — IPv6 Settings |

## Properties

Table 58.

Key Name | Value Type | Default Value | Value Description
--- | --- | --- | ---
    addr-gen-mode
    int32
    1
| Configure method for creating the address for use with RFC4862 IPv6 Stateless Address Autoconfiguration. The permitted values are: NM_SETTING_IP6_CONFIG_ADDR_GEN_MODE_EUI64 (0) or NM_SETTING_IP6_CONFIG_ADDR_GEN_MODE_STABLE_PRIVACY (1). If the property is set to EUI64, the addresses will be generated using the interface tokens derived from hardware address. This makes the host part of the address to stay constant, making it possible to track host's presence when it changes networks. The address changes when the interface hardware is replaced. The value of stable-privacy enables use of cryptographically secure hash of a secret host-specific key along with the connection's stable-id and the network address as specified by RFC7217. This makes it impossible to use the address track host's presence, and makes the address stable when the network interface hardware is replaced. On D-Bus, the absence of an addr-gen-mode setting equals enabling stable-privacy. For keyfile plugin, the absence of the setting on disk means 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.
    address-data
    array of vardict
| Array of IPv6 addresses. Each address dictionary contains at least 'address' and 'prefix' entries, containing the IP address as a string, and the prefix length as a uint32. Additional attributes may also exist on some addresses.
    addresses
    array of legacy IPv6 address struct (a(ayuay))
| Deprecated in favor of the 'address-data' and 'gateway' properties, but this can be used for backward-compatibility with older daemons. Note that if you send this property the daemon will ignore 'address-data' and 'gateway'. Array of IPv6 address structures. Each IPv6 address structure is composed of an IPv6 address, a prefix length (1 - 128), and an IPv6 gateway address. The gateway may be zeroed out if no gateway exists for that subnet.
    dad-timeout
    int32
    -1
| Timeout in milliseconds used to check for the presence of duplicate IP addresses on the network. If an address conflict is detected, the activation will fail. A zero value means that no duplicate address detection is performed, -1 means the default value (either configuration ipvx.dad-timeout override or zero). A value greater than zero is a timeout in milliseconds. The property is currently implemented only for IPv4.
    dhcp-duid
    string
| A string containing the DHCPv6 Unique Identifier (DUID) used by the dhcp client to identify itself to DHCPv6 servers (RFC 3315). The DUID is carried in the Client Identifier option. If the property is a hex string ('aa:bb:cc') it is interpreted as a binary DUID and filled as an opaque value in the Client Identifier option. The special value "lease" will retrieve the DUID previously used from the lease file belonging to the connection. If no DUID is found and "dhclient" is the configured dhcp client, the DUID is searched in the system-wide dhclient lease file. If still no DUID is found, or another dhcp client is used, a global and permanent DUID-UUID (RFC 6355) will be generated based on the machine-id. The special values "llt" and "ll" will generate a DUID of type LLT or LL (see RFC 3315) based on the current MAC address of the device. In order to try providing a stable DUID-LLT, the time field will contain a constant timestamp that is used globally (for all profiles) and persisted to disk. The special values "stable-llt", "stable-ll" and "stable-uuid" will generate a DUID of the corresponding type, derived from the connection's stable-id and a per-host unique key. You may want to include the "${DEVICE}" or "${MAC}" specifier in the stable-id, in case this profile gets activated on multiple devices. So, the link-layer address of "stable-ll" and "stable-llt" will be a generated address derived from the stable id. The DUID-LLT time value in the "stable-llt" option will be picked among a static timespan of three years (the upper bound of the interval is the same constant timestamp used in "llt"). When the property is unset, the global value provided for "ipv6.dhcp-duid" is used. If no global value is provided, the default "lease" value is assumed.
    dhcp-hostname
    string
| If the "dhcp-send-hostname" property is TRUE, then the specified name will be sent to the DHCP server when acquiring a lease. This property and "dhcp-fqdn" are mutually exclusive and cannot be set at the same time.
    dhcp-hostname-flags
    uint32
    0
| Flags for the DHCP hostname and FQDN. Currently this property only includes flags to control the FQDN flags set in the DHCP FQDN option. Supported FQDN flags are NM_DHCP_HOSTNAME_FLAG_FQDN_SERV_UPDATE (0x1), NM_DHCP_HOSTNAME_FLAG_FQDN_ENCODED (0x2) and NM_DHCP_HOSTNAME_FLAG_FQDN_NO_UPDATE (0x4). When no FQDN flag is set and NM_DHCP_HOSTNAME_FLAG_FQDN_CLEAR_FLAGS (0x8) is set, the DHCP FQDN option will contain no flag. Otherwise, if no FQDN flag is set and NM_DHCP_HOSTNAME_FLAG_FQDN_CLEAR_FLAGS (0x8) is not set, the standard FQDN flags are set in the request: NM_DHCP_HOSTNAME_FLAG_FQDN_SERV_UPDATE (0x1), NM_DHCP_HOSTNAME_FLAG_FQDN_ENCODED (0x2) for IPv4 and NM_DHCP_HOSTNAME_FLAG_FQDN_SERV_UPDATE (0x1) for IPv6. When this property is set to the default value NM_DHCP_HOSTNAME_FLAG_NONE (0x0), a global default is looked up in NetworkManager configuration. If that value is unset or also NM_DHCP_HOSTNAME_FLAG_NONE (0x0), then the standard FQDN flags described above are sent in the DHCP requests.
    dhcp-iaid
    string
| A string containing the "Identity Association Identifier" (IAID) used by the DHCP client. The property is a 32-bit decimal value or a special value among "mac", "perm-mac", "ifname" and "stable". When set to "mac" (or "perm-mac"), the last 4 bytes of the current (or permanent) MAC address are used as IAID. When set to "ifname", the IAID is computed by hashing the interface name. The special value "stable" can be used to generate an IAID based on the stable-id (see connection.stable-id), a per-host key and the interface name. When the property is unset, the value from global configuration is used; if no global default is set then the IAID is assumed to be "ifname". Note that at the moment this property is ignored for IPv6 by dhclient, which always derives the IAID from the MAC address.
    dhcp-send-hostname
    boolean
    TRUE
| If TRUE, a hostname is sent to the DHCP server when acquiring a lease. Some DHCP servers use this hostname to update DNS databases, essentially providing a static hostname for the computer. If the "dhcp-hostname" property is NULL and this property is TRUE, the current persistent hostname of the computer is sent.
    dhcp-timeout
    int32
    0
| A timeout for a DHCP transaction in seconds. If zero (the default), a globally configured default is used. If still unspecified, a device specific timeout is used (usually 45 seconds). Set to 2147483647 (MAXINT32) for infinity.
    dns
    array of byte array
| Array of IP addresses of DNS servers (in network byte order)
    dns-options
    array of string
| Array of DNS options as described in man 5 resolv.conf. NULL means that the options are unset and left at the default. In this case NetworkManager will use default options. This is distinct from an empty list of properties. The currently supported options are "attempts", "debug", "edns0", "inet6", "ip6-bytestring", "ip6-dotint", "ndots", "no-check-names", "no-ip6-dotint", "no-reload", "no-tld-query", "rotate", "single-request", "single-request-reopen", "timeout", "trust-ad", "use-vc". The "trust-ad" setting is only honored if the profile contributes name servers to resolv.conf, and if all contributing profiles have "trust-ad" enabled.
    dns-priority
    int32
    0
| DNS servers priority. The relative priority for DNS servers specified by this setting. A lower value is better (higher priority). Zero selects a globally configured default value. If the latter is missing or zero too, it defaults to 50 for VPNs (including WireGuard) and 100 for other connections. Note that the priority is to order DNS settings for multiple active connections. It does not disambiguate multiple DNS servers within the same connection profile. When using dns=default, servers with higher priority will be on top of resolv.conf. To prioritize a given server over another one within the same connection, just specify them in the desired order. When multiple devices have configurations with the same priority, VPNs will be considered first, then devices with the best (lowest metric) default route and then all other devices. Negative values have the special effect of excluding other configurations with a greater priority value; so in presence of at least one negative priority, only DNS servers from connections with the lowest priority value will be used. When using a DNS resolver that supports Conditional Forwarding as dns=dnsmasq or dns=systemd-resolved, each connection is used to query domains in its search list. Queries for domains not present in any search list are routed through connections having the '~.' special wildcard domain, which is added automatically to connections with the default route (or can be added manually). When multiple connections specify the same domain, the one with the highest priority (lowest numerical value) wins. If a connection specifies a domain which is subdomain of another domain with a negative DNS priority value, the subdomain is ignored.
    dns-search
    array of string
| Array of DNS search domains. Domains starting with a tilde ('~') are considered 'routing' domains and are used only to decide the interface over which a query must be forwarded; they are not used to complete unqualified host names.
    gateway
    string
| The gateway associated with this configuration. This is only meaningful if "addresses" is also set. The gateway's main purpose is to control the next hop of the standard default route on the device. Hence, the gateway property conflicts with "never-default" and will be automatically dropped if the IP configuration is set to never-default. As an alternative to set the gateway, configure a static default route with /0 as prefix length.
    ignore-auto-dns
    boolean
    FALSE
| When "method" is set to "auto" and this property to TRUE, automatically configured nameservers and search domains are ignored and only nameservers and search domains specified in the "dns" and "dns-search" properties, if any, are used.
    ignore-auto-routes
    boolean
    FALSE
| When "method" is set to "auto" and this property to TRUE, automatically configured routes are ignored and only routes specified in the "routes" property, if any, are used.
    ip6-privacy
    NMSettingIP6ConfigPrivacy (int32)
| Configure IPv6 Privacy Extensions for SLAAC, described in RFC4941. If enabled, it makes the kernel generate a temporary IPv6 address in addition to the public one generated from MAC address via modified EUI-64. This enhances privacy, but could cause problems in some applications, on the other hand. The permitted values are: -1: unknown, 0: disabled, 1: enabled (prefer public address), 2: enabled (prefer temporary addresses). Having a per-connection setting set to "-1" (unknown) means fallback to global configuration "ipv6.ip6-privacy". If also global configuration is unspecified or set to "-1", fallback to read "/proc/sys/net/ipv6/conf/default/use_tempaddr". Note that this setting is distinct from the Stable Privacy addresses that can be enabled with the "addr-gen-mode" property's "stable-privacy" setting as another way of avoiding host tracking with IPv6 addresses.
    may-fail
    boolean
    TRUE
| If TRUE, allow overall network configuration to proceed even if the configuration specified by this property times out. Note that at least one IP configuration must succeed or overall network configuration will still fail. For example, in IPv6-only networks, setting this property to TRUE on the NMSettingIP4Config allows the overall network configuration to succeed if IPv4 configuration fails but IPv6 configuration completes successfully.
    method
    string
| IP configuration method. NMSettingIP4Config and NMSettingIP6Config both support "disabled", "auto", "manual", and "link-local". See the subclass-specific documentation for other values. In general, for the "auto" method, properties such as "dns" and "routes" specify information that is added on to the information returned from automatic configuration. The "ignore-auto-routes" and "ignore-auto-dns" properties modify this behavior. For methods that imply no upstream network, such as "shared" or "link-local", these properties must be empty. For IPv4 method "shared", the IP subnet can be configured by adding one manual IPv4 address or otherwise 10.42.x.0/24 is chosen. Note that the shared method must be configured on the interface which shares the internet to a subnet, not on the uplink which is shared.
    never-default
    boolean
    FALSE
| If TRUE, this connection will never be the default connection for this IP type, meaning it will never be assigned the default route by NetworkManager.
    ra-timeout
    int32
    0
| A timeout for waiting Router Advertisements in seconds. If zero (the default), a globally configured default is used. If still unspecified, the timeout depends on the sysctl settings of the device. Set to 2147483647 (MAXINT32) for infinity.
    route-data
    array of vardict
| Array of IPv6 routes. Each route dictionary contains at least 'dest' and 'prefix' entries, containing the destination IP address as a string, and the prefix length as a uint32. Most routes will also have a 'next-hop' entry, containing the next hop IP address as a string. If the route has a 'metric' entry (containing a uint32), that will be used as the metric for the route (otherwise NM will pick a default value appropriate to the device). Additional attributes may also exist on some routes.
    route-metric
    int64
    -1
| The default metric for routes that don't explicitly specify a metric. The default value -1 means that the metric is chosen automatically based on the device type. The metric applies to dynamic routes, manual (static) routes that don't have an explicit metric setting, address prefix routes, and the default route. Note that for IPv6, the kernel accepts zero (0) but coerces it to 1024 (user default). Hence, setting this property to zero effectively mean setting it to 1024. For IPv4, zero is a regular value for the metric.
    route-table
    uint32
    0
| Enable policy routing (source routing) and set the routing table used when adding routes. This affects all routes, including device-routes, IPv4LL, DHCP, SLAAC, default-routes and static routes. But note that static routes can individually overwrite the setting by explicitly specifying a non-zero routing table. If the table setting is left at zero, it is eligible to be overwritten via global configuration. If the property is zero even after applying the global configuration value, policy routing is disabled for the address family of this connection. Policy routing disabled means that NetworkManager will add all routes to the main table (except static routes that explicitly configure a different table). Additionally, NetworkManager will not delete any extraneous routes from tables except the main table. This is to preserve backward compatibility for users who manage routing tables outside of NetworkManager.
    routes
    array of legacy IPv6 route struct (a(ayuayu))
| Deprecated in favor of the 'route-data' property, but this can be used for backward-compatibility with older daemons. Note that if you send this property the daemon will ignore 'route-data'. Array of IPv6 route structures. Each IPv6 route structure is composed of an IPv6 address, a prefix length (1 - 128), an IPv6 next hop address (which may be zeroed out if there is no next hop), and a metric. If the metric is 0, NM will choose an appropriate default metric for the device.
    token
    string
| Configure the token for draft-chown-6man-tokenised-ipv6-identifiers-02 IPv6 tokenized interface identifiers. Useful with eui64 addr-gen-mode.