doc/user/ipv6.rst

   1 .. _ipv6-support:
   2
   3 ************
   4 IPv6 Support
   5 ************
   6
   7 FRR fully supports IPv6 routing.  As described so far, FRR supports RIPng,
   8 OSPFv3, and BGP-4+.  You can give IPv6 addresses to an interface and configure
   9 static IPv6 routing information.  FRR IPv6 also provides automatic address
  10 configuration via a feature called ``address auto configuration``.  To do it,
  11 the router must send router advertisement messages to the all nodes that exist
  12 on the network.
  13
  14 Previous versions of FRR could be built without IPv6 support.  This is
  15 no longer possible.
  16
  17 Router Advertisement
  18 ====================
  19
  20 .. index:: no ipv6 nd suppress-ra
  21 .. clicmd:: no ipv6 nd suppress-ra
  22
  23    Send router advertisement messages.
  24
  25 .. index:: ipv6 nd suppress-ra
  26 .. clicmd:: ipv6 nd suppress-ra
  27
  28    Don't send router advertisement messages.
  29
  30 .. index:: ipv6 nd prefix ipv6prefix [valid-lifetime] [preferred-lifetime] [off-link] [no-autoconfig] [router-address]
  31 .. clicmd:: ipv6 nd prefix ipv6prefix [valid-lifetime] [preferred-lifetime] [off-link] [no-autoconfig] [router-address]
  32
  33    Configuring the IPv6 prefix to include in router advertisements. Several prefix
  34    specific optional parameters and flags may follow:
  35
  36    - ``valid-lifetime``: the length of time in seconds during what the prefix is
  37      valid for the purpose of on-link determination. Value ``infinite`` represents
  38      infinity (i.e. a value of all one bits (``0xffffffff``)).
  39      Range: ``(0-4294967295)``  Default: ``2592000``
  40
  41    - ``preferred-lifetime``: the length of time in seconds during what addresses
  42      generated from the prefix remain preferred. Value ``infinite`` represents
  43      infinity.
  44      Range: ``(0-4294967295)``  Default: ``604800``
  45
  46    - ``off-link``: indicates that advertisement makes no statement about on-link or
  47      off-link properties of the prefix.
  48      Default: not set, i.e. this prefix can be used for on-link determination.
  49
  50    - ``no-autoconfig``: indicates to hosts on the local link that the specified prefix
  51      cannot be used for IPv6 autoconfiguration.
  52
  53      Default: not set, i.e. prefix can be used for autoconfiguration.
  54
  55    - ``router-address``: indicates to hosts on the local link that the specified
  56      prefix contains a complete IP address by setting R flag.
  57
  58      Default: not set, i.e. hosts do not assume a complete IP address is placed.
  59
  60 .. index::
  61    single: no ipv6 nd ra-interval [(1-1800)]
  62    single: no ipv6 nd ra-interval [(1-1800)]
  63 .. clicmd:: [no] ipv6 nd ra-interval [(1-1800)]
  64
  65    The maximum time allowed between sending unsolicited multicast router
  66    advertisements from the interface, in seconds.
  67    Default: ``600``
  68
  69 .. index:: ipv6 nd ra-interval msec (70-1800000)
  70 .. index::
  71    single: no ipv6 nd ra-interval [msec (70-1800000)]
  72    single: ipv6 nd ra-interval msec (70-1800000)
  73 .. clicmd:: [no] ipv6 nd ra-interval [msec (70-1800000)]
  74
  75    The maximum time allowed between sending unsolicited multicast router
  76    advertisements from the interface, in milliseconds.
  77    Default: ``600000``
  78
  79 .. index::
  80    single: ipv6 nd ra-fast-retrans
  81    single: no ipv6 nd ra-fast-retrans
  82 .. clicmd:: [no] ipv6 nd ra-fast-retrans
  83
  84    RFC4861 states that consecutive RA packets should be sent no more
  85    frequently than three seconds apart. FRR by default allows faster
  86    transmissions of RA packets in order to speed convergence and
  87    neighbor establishment, particularly for unnumbered peering.  By
  88    turning off ipv6 nd ra-fast-retrans, the implementation is
  89    compliant with the RFC at the cost of slower convergence
  90    and neighbor establishment.
  91    Default: enabled
  92
  93 .. index::
  94    single: ipv6 nd ra-retrans-interval (0-4294967295)
  95    single: no ipv6 nd retrans-interval [(0-4294967295)]
  96 .. clicmd:: [no] ipv6 nd ra-retrans-interval [(0-4294967295)]
  97
  98    The value to be placed in the retrans timer field of router advertisements
  99    sent from the interface, in msec. Indicates the interval between router
 100    advertisement retransmissions. Setting the value to zero indicates that
 101    the value is unspecified by this router. Must be between zero or 4294967295
 102    msec.
 103    Default: ``0``
 104
 105 .. index::
 106    single: ipv6 nd ra-hop-limit (0-255)
 107    single: no ipv6 nd ra-hop-limit [(0-255)]
 108 .. clicmd:: [no] ipv6 nd ra-hop-limit [(0-255)]
 109
 110    The value to be placed in the hop count field of router advertisements sent
 111    from the interface, in hops. Indicates the maximum diameter of the network.
 112    Setting the value to zero indicates that the value is unspecified by this
 113    router.  Must be between zero or 255 hops.
 114    Default: ``64``
 115
 116 .. index::
 117    single: ipv6 nd ra-lifetime (0-9000)
 118    single: no ipv6 nd ra-lifetime [(0-9000)]
 119 .. clicmd:: [no] ipv6 nd ra-lifetime [(0-9000)]
 120
 121    The value to be placed in the Router Lifetime field of router advertisements
 122    sent from the interface, in seconds. Indicates the usefulness of the router
 123    as a default router on this interface. Setting the value to zero indicates
 124    that the router should not be considered a default router on this interface.
 125    Must be either zero or between value specified with ``ipv6 nd ra-interval``
 126    (or default) and 9000 seconds.
 127    Default: ``1800``
 128
 129 .. index::
 130    single: no ipv6 nd reachable-time [(1-3600000)]
 131    single: ipv6 nd reachable-time (1-3600000)
 132 .. clicmd:: [no] ipv6 nd reachable-time [(1-3600000)]
 133
 134    The value to be placed in the Reachable Time field in the Router
 135    Advertisement messages sent by the router, in milliseconds. The configured
 136    time enables the router to detect unavailable neighbors. The value zero
 137    means unspecified (by this router).
 138    Default: ``0``
 139
 140 .. index::
 141    single: ipv6 nd managed-config-flag
 142    single: no ipv6 nd managed-config-flag
 143 .. clicmd:: [no] ipv6 nd managed-config-flag
 144
 145    Set/unset flag in IPv6 router advertisements which indicates to hosts that
 146    they should use managed (stateful) protocol for addresses autoconfiguration
 147    in addition to any addresses autoconfigured using stateless address
 148    autoconfiguration.
 149    Default: not set
 150
 151 .. index::
 152    single: ipv6 nd other-config-flag
 153    single: no ipv6 nd other-config-flag
 154 .. clicmd:: [no] ipv6 nd other-config-flag
 155
 156    Set/unset flag in IPv6 router advertisements which indicates to hosts that
 157    they should use administered (stateful) protocol to obtain autoconfiguration
 158    information other than addresses.
 159    Default: not set
 160
 161 .. index::
 162    single: ipv6 nd home-agent-config-flag
 163    single: no ipv6 nd home-agent-config-flag
 164 .. clicmd:: [no] ipv6 nd home-agent-config-flag
 165
 166    Set/unset flag in IPv6 router advertisements which indicates to hosts that
 167    the router acts as a Home Agent and includes a Home Agent Option.
 168    Default: not set
 169
 170 .. index:: ipv6 nd home-agent-preference (0-65535)
 171
 172 .. index::
 173    single: no ipv6 nd home-agent-preference [(0-65535)]
 174    single: ipv6 nd home-agent-preference (0-65535)
 175 .. clicmd:: [no] ipv6 nd home-agent-preference [(0-65535)]
 176
 177    The value to be placed in Home Agent Option, when Home Agent config flag is
 178    set, which indicates to hosts Home Agent preference. The default value of 0
 179    stands for the lowest preference possible.
 180    Default: ``0``
 181
 182 .. index::
 183    single: ipv6 nd home-agent-lifetime (0-65520)
 184    single: no ipv6 nd home-agent-lifetime (0-65520)
 185 .. clicmd:: [no] ipv6 nd home-agent-lifetime [(0-65520)]
 186
 187    The value to be placed in Home Agent Option, when Home Agent config flag is set,
 188    which indicates to hosts Home Agent Lifetime. The default value of 0 means to
 189    place the current Router Lifetime value.
 190
 191    Default: ``0``
 192
 193 .. index::
 194    single: ipv6 nd adv-interval-option
 195    single: no ipv6 nd adv-interval-option
 196 .. clicmd:: [no] ipv6 nd adv-interval-option
 197
 198    Include an Advertisement Interval option which indicates to hosts the maximum time,
 199    in milliseconds, between successive unsolicited Router Advertisements.
 200    Default: not set
 201
 202 .. index::
 203    single: ipv6 nd router-preference (high|medium|low)
 204    single: no ipv6 nd router-preference (high|medium|low)
 205 .. clicmd:: [no] ipv6 nd router-preference [(high|medium|low)]
 206
 207    Set default router preference in IPv6 router advertisements per RFC4191.
 208    Default: medium
 209
 210 .. index::
 211    single: ipv6 nd mtu (1-65535)
 212    single: no ipv6 nd mtu [(1-65535)]
 213 .. clicmd:: [no] ipv6 nd mtu [(1-65535)]
 214
 215    Include an MTU (type 5) option in each RA packet to assist the attached
 216    hosts in proper interface configuration. The announced value is not verified
 217    to be consistent with router interface MTU.
 218
 219    Default: don't advertise any MTU option.
 220
 221 .. index::
 222    single: ipv6 nd rdnss ipv6address [lifetime]
 223    single: no ipv6 nd rdnss ipv6address [lifetime]
 224 .. clicmd:: [no] ipv6 nd rdnss ipv6address [lifetime]
 225
 226    Recursive DNS server address to advertise using the RDNSS (type 25) option
 227    described in RFC8106. Can be specified more than once to advertise multiple
 228    addresses. Note that hosts may choose to limit the number of RDNSS addresses
 229    to track.
 230
 231    Optional parameter:
 232
 233    - ``lifetime``: the maximum time in seconds over which the specified address
 234      may be used for domain name resolution. Value ``infinite`` represents
 235      infinity (i.e. a value of all one bits (``0xffffffff``)). A value of 0
 236      indicates that the address must no longer be used.
 237      Range: ``(0-4294967295)``  Default: ``3 * ra-interval``
 238
 239    Default: do not emit RDNSS option
 240
 241 .. index::
 242    single: ipv6 nd dnssl domain-name-suffix [lifetime]
 243    single: no ipv6 nd dnssl domain-name-suffix [lifetime]
 244 .. clicmd:: [no] ipv6 nd dnssl domain-name-suffix [lifetime]
 245
 246    Advertise DNS search list using the DNSSL (type 31) option described in
 247    RFC8106. Specify more than once to advertise multiple domain name suffixes.
 248    Host implementations may limit the number of honored search list entries.
 249
 250    Optional parameter:
 251
 252    - ``lifetime``: the maximum time in seconds over which the specified domain
 253      suffix may be used in the course of  name resolution. Value ``infinite``
 254      represents infinity (i.e. a value of all one bits (``0xffffffff``)). A
 255      value of 0 indicates that the name suffix must no longer be used.
 256      Range: ``(0-4294967295)``  Default: ``3 * ra-interval``
 257
 258    Default: do not emit DNSSL option
 259
 260 Router Advertisement Configuration Example
 261 ==========================================
 262 A small example:
 263
 264 .. code-block:: frr
 265
 266    interface eth0
 267     no ipv6 nd suppress-ra
 268     ipv6 nd prefix 2001:0DB8:5009::/64
 269
 270
 271 .. seealso::
 272
 273    - :rfc:`2462` (IPv6 Stateless Address Autoconfiguration)
 274    - :rfc:`4861` (Neighbor Discovery for IP Version 6 (IPv6))
 275    - :rfc:`6275` (Mobility Support in IPv6)
 276    - :rfc:`4191` (Default Router Preferences and More-Specific Routes)
 277    - :rfc:`8106` (IPv6 Router Advertisement Options for DNS Configuration)