radvd.conf(5)


NAME

   radvd.conf  -  configuration  file  of  the router advertisement daemon
   radvd

DESCRIPTION

   This file describes the information which is  included  in  the  router
   advertisement (RA) of a specific interface.

   The file contains one or more interface definitions of the form:

   interface name {
        list of interface specific options
        list of prefix definitions
        list of clients (IPv6 addresses) to advertise to
        list of route definitions
        list of RDNSS definitions
        list of DNSSL definitions
        list of ABRO definitions
   };

   All  the  possible interface specific options are detailed below.  Each
   option has to be terminated by a semicolon.

   Prefix definitions are of the form:

   prefix prefix/length {
        list of prefix specific options
   };

   Prefix can be network prefix or the  address  of  the  interface.   The
   address of interface should be used when using Mobile IPv6 extensions.

   Special  prefix  "::/64"  is  also  supported on systems that implement
   getifaddrs() (on other  systems,  configuration  activation  fails  and
   radvd  exits).   When configured, radvd picks all non-link-local prefix
   assigned to the interface and  starts  advertising  it.   This  may  be
   applicable  in  non-6to4  scenarios  where  the  upstream  prefix might
   change.  This option is  incompatible  with  Base6to4Interface  option.
   AdvRouterAddr option is always enabled when this configuration is used.

   All  the  possible  prefix  specific options are described below.  Each
   option has to be terminated by a semicolon.

   Decimal   values   are    allowed    only    for    MinDelayBetweenRAs,
   MaxRtrAdvInterval and MinRtrAdvInterval.  Decimal values should be used
   only when using Mobile IPv6 extensions.

   Route definitions are of the form:

   route prefix/length {
        list of route specific options
   };

   The prefix of a route definition should be network prefix;  it  can  be
   used to advertise more specific routes to the hosts.

   RDNSS (Recursive DNS server) definitions are of the form:

   RDNSS ip [ip] [ip] {
        list of rdnss specific options
   };

   DNSSL (DNS Search List) definitions are of the form:

   DNSSL suffix [suffix] [suffix] [...] {
        list of dnssl specific options
   };

   By  default  radvd will send route advertisements so that every node on
   the link can use them.  The list of clients (IPv6 address) to advertise
   to,  and  accept  route solicitations from can be configured.  If done,
   radvd does not send send messages to the multicast addresses but to the
   configured  unicast addresses only.  Solicitations from other addresses
   are refused.  This is similar  to  UnicastOnly  but  includes  periodic
   messages  and  incoming  client  access  configuration.   See  examples
   section for a use case of this.

   The definitions are of the form:

   clients {
           list of IPv6 addresses
   };

   ABRO (Authoritative Border Router Option) definitions are of the form:

   abro IPv6-address {
           list of abro specific options
   };

INTERFACE SPECIFIC OPTIONS

   IgnoreIfMissing on|off

          A flag indicating whether or not the interface is ignored if  it
          does not exist at start-up.  By default, radvd exits.

          This  is useful for dynamic interfaces which are not active when
          radvd starts or which are dynamically  disabled  and  re-enabled
          during the time radvd runs.

          Current   versions  of  radvd  automatically  try  to  re-enable
          interfaces.

          Enabling IgnoreIfMissing also quenches certain warnings  in  log
          messages relating to missing interfaces.

          Default: on

   AdvSendAdvert on|off

          A  flag  indicating  whether  or  not  the router sends periodic
          router advertisements and responds to router solicitations.

          This option no longer has to be specified first, but it needs to
          be on to enable advertisement on this interface.

          Default: off

   UnicastOnly on|off

          Indicates  that  the  interface link type only supports unicast.
          This will prevent unsolicited advertisements  from  being  sent,
          and  will  cause  solicited  advertisements to be unicast to the
          soliciting node.  This option is  necessary  for  non-broadcast,
          multiple-access links, such as ISATAP.

          Default: off

   MaxRtrAdvInterval seconds

          The  maximum  time allowed between sending unsolicited multicast
          router advertisements from the interface, in seconds.

          Must be no less than 4 seconds and no greater than 1800 seconds.

          Minimum when using Mobile IPv6 extensions: 0.07.

          For values less than 0.2  seconds,  0.02  seconds  is  added  to
          account for scheduling granularities as specified in RFC3775.

          Default: 600 seconds

   MinRtrAdvInterval seconds

          The  minimum  time allowed between sending unsolicited multicast
          router advertisements from the interface, in seconds.

          Must be no less than 3  seconds  and  no  greater  than  0.75  *
          MaxRtrAdvInterval.

          Minimum when using Mobile IPv6 extensions: 0.03.

          Default: 0.33 * MaxRtrAdvInterval

   MinDelayBetweenRAs seconds

          The  minimum  time  allowed  between  sending  multicast  router
          advertisements from the interface, in seconds.

          This applies to solicited multicast RAs.  This is defined as the
          protocol   constant  MIN_DELAY_BETWEEN_RAS  in  RFC4861.   MIPv6
          redefines this parameter to have a minimum of 0.03 seconds.

          Minimum when using Mobile IPv6 extensions: 0.03.

          Default: 3

   AdvManagedFlag on|off

          When set, hosts use the  administered  (stateful)  protocol  for
          address   autoconfiguration   in   addition   to  any  addresses
          autoconfigured using stateless address  autoconfiguration.   The
          use of this flag is described in RFC 4862.

          Default: off

   AdvOtherConfigFlag on|off

          When  set,  hosts  use  the administered (stateful) protocol for
          autoconfiguration of other (non-address) information.   The  use
          of this flag is described in RFC 4862.

          Default: off

   AdvLinkMTU integer

          The  MTU  option  is  used  in  router advertisement messages to
          insure that all nodes on a link use the same MTU value in  those
          cases where the link MTU is not well known.

          If  specified, i.e. not 0, must not be smaller than 1280 and not
          greater than  the  maximum  MTU  allowed  for  this  link  (e.g.
          ethernet has a maximum MTU of 1500. See RFC 4864).

          Default: 0

   AdvReachableTime milliseconds

          The  time,  in  milliseconds,  that a node assumes a neighbor is
          reachable after having  received  a  reachability  confirmation.
          Used  by  the  Neighbor  Unreachability Detection algorithm (see
          Section 7.3 of RFC 4861).  A value of zero means unspecified (by
          this router).

          Must be no greater than 3,600,000 milliseconds (1 hour).

          Default: 0

   AdvRetransTimer milliseconds

          The   time,  in  milliseconds,  between  retransmitted  Neighbor
          Solicitation messages.   Used  by  address  resolution  and  the
          Neighbor  Unreachability  Detection  algorithm (see Sections 7.2
          and 7.3 of RFC 4861).  A value of  zero  means  unspecified  (by
          this router).

          Default: 0

   AdvCurHopLimit integer

          The  default  value that should be placed in the Hop Count field
          of the IP header for outgoing (unicast) IP packets.   The  value
          should  be  set  to  the  current diameter of the Internet.  The
          value zero means unspecified (by this router).

          Default: 64

   AdvDefaultLifetime seconds

          The lifetime associated with the  default  router  in  units  of
          seconds.   The  maximum  value  corresponds  to  18.2  hours.  A
          lifetime of 0 indicates that the router is not a default  router
          and  should  not  appear on the default router list.  The router
          lifetime applies only to the router's usefulness  as  a  default
          router;  it  does  not  apply  to information contained in other
          message fields or options.  Options that need  time  limits  for
          their information include their own lifetime fields.

          Must  be  either  zero  or  between  MaxRtrAdvInterval  and 9000
          seconds.

          Default: 3 * MaxRtrAdvInterval (Minimum 1 second).

   AdvDefaultPreference low|medium|high

          The preference associated with the  default  router,  as  either
          "low", "medium", or "high".

          Default: medium

   AdvSourceLLAddress on|off

          When  set,  the  link-layer address of the outgoing interface is
          included in the RA.

          Default: on

   AdvHomeAgentFlag on|off

          When set, indicates that sending router  is  able  to  serve  as
          Mobile  IPv6  Home Agent.  When set, minimum limits specified by
          Mobile    IPv6    are    used    for    MinRtrAdvInterval    and
          MaxRtrAdvInterval.

          Default: off

   AdvHomeAgentInfo on|off

          When  set,  Home  Agent  Information Option (specified by Mobile
          IPv6) is included in  Router  Advertisements.   AdvHomeAgentFlag
          must also be set when using this option.

          Default: off

   HomeAgentLifetime seconds

          The  length  of time in seconds (relative to the time the packet
          is sent) that the router is  offering  Mobile  IPv6  Home  Agent
          services.   A value 0 must not be used.  The maximum lifetime is
          65520  seconds  (18.2  hours).   This  option  is  ignored,   if
          AdvHomeAgentInfo is not set.

          If  both  HomeAgentLifetime  and  HomeAgentPreference are set to
          their default values, Home Agent Information Option will not  be
          sent.

          Default: AdvDefaultLifetime

   HomeAgentPreference integer

          The   preference   for   the  Home  Agent  sending  this  Router
          Advertisement.  Values greater than 0 indicate  more  preferable
          Home  Agent,  values  less  than 0 indicate less preferable Home
          Agent.  This option is ignored, if AdvHomeAgentInfo is not set.

          If both HomeAgentLifetime and  HomeAgentPreference  are  set  to
          their  default values, Home Agent Information Option will not be
          sent.

          Default: 0

   AdvMobRtrSupportFlag on|off

          When set, the Home  Agent  signals  it  supports  Mobile  Router
          registrations  (specified by NEMO Basic).  AdvHomeAgentInfo must
          also be set when using this option.

          Default: off

   AdvIntervalOpt on|off

          When set, Advertisement Interval  Option  (specified  by  Mobile
          IPv6)  is  included in Router Advertisements.  When set, minimum
          limits specified by Mobile IPv6 are used  for  MinRtrAdvInterval
          and MaxRtrAdvInterval.

          The   advertisement   interval   is   based  on  the  configured
          MaxRtrAdvInterval parameter  except  where  this  is  less  than
          200ms.    In   this   case,   the   advertised   interval  is  (
          MaxRtrAdvInterval + 20ms ).

          Default: off

PREFIX SPECIFIC OPTIONS

   AdvOnLink on|off

          When set, indicates that this prefix can  be  used  for  on-link
          determination.    When   not  set  the  advertisement  makes  no
          statement about on-link or off-link properties  of  the  prefix.
          For instance, the prefix might be used for address configuration
          with some of the addresses belonging to the prefix being on-link
          and others being off-link.

          Default: on

   AdvAutonomous on|off

          When  set, indicates that this prefix can be used for autonomous
          address configuration as specified in RFC 4862.

          Default: on

   AdvRouterAddr on|off

          When set, indicates  that  the  address  of  interface  is  sent
          instead  of network prefix, as is required by Mobile IPv6.  When
          set, minimum limits  specified  by  Mobile  IPv6  are  used  for
          MinRtrAdvInterval and MaxRtrAdvInterval.

          Default: off

   AdvValidLifetime seconds|infinity

          The  length  of time in seconds (relative to the time the packet
          is sent) that the prefix is valid for  the  purpose  of  on-link
          determination.   The symbolic value infinity represents infinity
          (i.e. a value of all one bits (0xffffffff)).  The valid lifetime
          is also used by RFC 4862.

          Note  that  clients  will ignore AdvValidLifetime of an existing
          prefix if the lifetime is below two hours, as  required  in  RFC
          4862 Section 5.5.3 point e).

          Note: RFC4861's suggested default value is significantly longer:
          30 days.

          Default: 86400 seconds (1 day)

   AdvPreferredLifetime seconds|infinity

          The length of time in seconds (relative to the time  the  packet
          is  sent) that addresses generated from the prefix via stateless
          address autoconfiguration remain preferred.  The symbolic  value
          infinity  represents  infinity  (i.e.  a  value  of all one bits
          (0xffffffff)).  See RFC 4862.

          Note: RFC4861's suggested default value is significantly longer:
          7 days.

          Default: 14400 seconds (4 hours)

   DeprecatePrefix on|off

          Upon  shutdown,  this  option  will cause radvd to deprecate the
          prefix by announcing it in the radvd shutdown  RA  with  a  zero
          preferred  lifetime and a valid lifetime slightly greater than 2
          hours. This  will  encourage  end-nodes  using  this  prefix  to
          deprecate  any  associated addresses immediately. Note that this
          option should only be used when only one  router  is  announcing
          the  prefix  onto  the  link, otherwise end-nodes will deprecate
          associated addresses despite the prefix still  being  valid  for
          preferred use.

          See  RFC4862, section 5.5.3., "Router Advertisement Processing",
          part (e).

          Default: off

   DecrementLifetimes on|off

          This  option  causes  radvd  to  decrement  the  values  of  the
          preferred  and  valid  lifetimes  for  the prefix over time. The
          lifetimes are decremented by the number  of  seconds  since  the
          last  RA.  If radvd receives a SIGUSR1 signal, it will reset the
          values of the preferred and valid lifetimes back to the  initial
          values  used by radvd when it started. If radvd never receives a
          SIGUSR1 signal, it will  continue  to  decrement  the  lifetimes
          until the preferred lifetime reaches zero. After a final RA with
          a zero value preferred lifetime, radvd will  cease  to  announce
          the  prefix. If a SIGUSR1 signal then causes the lifetimes to be
          reset, the prefix will then re-appear in the RAs.

          This option is intended to be used in conjunction with a  DHCPv6
          client  that  is  using  the  Identity  Association  for  Prefix
          Delegation (IA_PD) option to acquire a prefix from a  Delegating
          Router  for  use  by  a Requesting Router. In this scenario, the
          prefix(es) from within the delegated prefix that  are  announced
          by  radvd would age in parallel with and at the same rate as the
          delegated prefix, and expire at approximately the same time,  if
          the delegated prefix's life isn't extended.

          See RFC3633, "IPv6 Prefix Options for Dynamic Host Configuration
          Protocol (DHCP) version 6".

          Default: off

   Base6Interface name

          If this options is specified, this prefix will be combined  with
          the  IPv6  address  of  the  interface  specified  by name.  The
          resulting prefix length will be 64.

   Base6to4Interface name

          If this option is specified, this prefix will be  combined  with
          the  IPv4  address  of  interface  name  to produce a valid 6to4
          prefix. The first 16 bits of this prefix  will  be  replaced  by
          2002 and the next 32 bits of this prefix will be replaced by the
          IPv4 address assigned to interface name at  configuration  time.
          The  remaining 80 bits of the prefix (including the SLA ID) will
          be advertised as specified in the configuration file.   See  the
          next section for an example.

          If  interface  name  is  not  available at configuration time, a
          warning will be written to the  log  and  this  prefix  will  be
          disabled until radvd is reconfigured.

          This  option  enables  systems  with  dynamic  IPv4 addresses to
          update their advertised 6to4 prefixes simply by restarting radvd
          or sending a SIGHUP signal to cause radvd to reconfigure itself.

          Note  that  6to4 prefixes derived from dynamically-assigned IPv4
          addresses should be  advertised  with  a  significantly  shorter
          lifetime  (see  the  AdvValidLifetime  and  AdvPreferredLifetime
          options).

          For more information on 6to4, see RFC 3056.

          Default: 6to4 is not used

ROUTE SPECIFIC OPTIONS

   AdvRouteLifetime seconds|infinity

          The lifetime associated with the route in units of seconds.  The
          symbolic value infinity represents infinity (i.e. a value of all
          one bits (0xffffffff)).

          Default: 3 * MaxRtrAdvInterval

   AdvRoutePreference low|medium|high

          The preference associated with the  default  router,  as  either
          "low", "medium", or "high".

          Default: medium

   RemoveRoute on|off

          Upon  shutdown, announce this route with a zero second lifetime.
          This should cause the route to be immediately removed  from  the
          receiving end-nodes' route table.

          Default: on

RDNSS SPECIFIC OPTIONS

   AdvRDNSSLifetime seconds|infinity
          The  maximum  duration  how  long the RDNSS entries are used for
          name resolution. A value of  0  means  the  nameserver  must  no
          longer  be  used.  The  value,  if  not  0,  must  be  at  least
          MaxRtrAdvInterval.  To ensure stale RDNSS info gets removed in a
          timely    fashion,    this    should   not   be   greater   than
          2*MaxRtrAdvInterval.

          Default: 2*MaxRtrAdvInterval

   FlushRDNSS on|off

          Upon shutdown, announce the RDNSS entries  with  a  zero  second
          lifetime.   This   should   cause  the  RDNSS  addresses  to  be
          immediately removed from the end-nodes' list  of  Recursive  DNS
          Servers.

          Default: on

DNSSL SPECIFIC OPTIONS

   AdvDNSSLLifetime seconds|infinity;
          The  maximum  duration  how  long the DNSSL entries are used for
          name resolution.  A value of 0 means the suffix should no longer
          be   used.    The   value,   if   not   0,   must  be  at  least
          MaxRtrAdvInterval.  To ensure stale DNSSL info gets removed in a
          timely    fashion,    this    should   not   be   greater   than
          2*MaxRtrAdvInterval.

          Default: 2*MaxRtrAdvInterval

   FlushDNSSL on|off

          Upon shutdown, announce the DNSSL entries  with  a  zero  second
          lifetime.  This should cause the DNSSL entries to be immediately
          removed from the end-nodes' DNS search list.

          Default: on

ABRO SPECIFIC OPTIONS

   AdvValidLifeTime seconds
          The time in units of that the set of border  router  information
          is  valid.   A value of all zero bits assumes a default value of
          10,000(~one week).

   AdvVersionLow, AdvVersionHigh unsignedinteger
          Both forms 32-bit unsigned version number corresponding  to  the
          set of information contained in RA message.

EXAMPLES

   interface eth0
   {
           AdvSendAdvert on;
           prefix 2001:db8:0:1::/64
           {
                   AdvOnLink on;
                   AdvAutonomous on;
           };
   };

   It   says   that   router   advertisement   daemon   should   advertise
   (AdvSendAdvert on;) the prefix 2001:db8:0:1:: which has a length of  64
   on  the interface eth0.  Also the prefix should be marked as autonomous
   (AdvAutonomous on;) and as on-link  (AdvOnLink  on;).   All  the  other
   options are left on their default values.

   To  support movement detection of Mobile IPv6 Mobile Nodes, the address
   of interface should be used instead of network prefix:

   interface eth0
   {
           AdvSendAdvert on;
           prefix 2001:db8:0:1::4/64
           {
                   AdvOnLink on;
                   AdvAutonomous on;
                   AdvRouterAddr on;
           };
   };

   For 6to4 support, include the Base6to4Interface option in  each  prefix
   section.  When using a dynamic IPv4 address, set small prefix lifetimes
   to prevent hosts from retaining unreachable prefixes after a  new  IPv4
   address  has been assigned.  When advertising to on a dynamic interface
   (e.g., Bluetooth), skip the interface if it is not active yet.

   interface bnep0
   {
           IgnoreIfMissing on;
           AdvSendAdvert on;

           # Advertise at least every 30 seconds
           MaxRtrAdvInterval 30;

           prefix 0:0:0:5678::/64
           {
                   AdvOnLink on;
                   AdvAutonomous on;
                   Base6to4Interface ppp0;

                   # Very short lifetimes for dynamic addresses
                   AdvValidLifetime 300;
                   AdvPreferredLifetime 120;
           };
   };

   Since  6to4  is   enabled,   the   prefix   will   be   advertised   as
   2002:WWXX:YYZZ:5678::/64, where WW.XX.YY.ZZ is the IPv4 address of ppp0
   at configuration time.  (IPv6  addresses  are  written  in  hexadecimal
   whereas  IPv4  addresses  are  written  in decimal, so the IPv4 address
   WW.XX.YY.ZZ in the 6to4 prefix will be represented in hex.)

   In this specific case, the configuration scripts may send HUP signal to
   radvd  when  taking bnep0 up or down to notify about the status; in the
   current radvd releases, sending HUP is no  longer  mandatory  when  the
   link comes back up.

   interface eth0
   {
           AdvSendAdvert on;
           prefix 2001:db8:0:1::/64
           {
                   AdvOnLink on;
                   AdvAutonomous on;
           };
           clients
           {
                   fe80::21f:16ff:fe06:3aab;
                   fe80::21d:72ff:fe96:aaff;
           };
   };

   This    configuration    would    only    announce    the   prefix   to
   fe80::21f:16ff:fe06:3aab  and  fe80::21d:72ff:fe96:aaff.   Furthermore,
   all RA requests of other clients are denied.

   This  may  come  in  handy  if you want to roll out IPv6 only partially
   because some clients are broken or untested.

   For ABRO support
   interface lowpan0
   {
        AdvSendAdvert on;
        UnicastOnly on;
        AdvCurHopLimit 255;
        prefix 2001:0db8:0100:f101::/64 {
             AdvOnLink on;
             AdvAutonomous on;
             AdvRouterAddr on;
        };
        abro fe80::a200:0:0:1/64 {
             AdvVersionLow 10;
             AdvVersionHigh 2;
             AdvValidLifeTime 2;
        };
   };

FILES

   /usr/sbin/radvd
   /etc/radvd.conf
   /var/run/radvd.pid
   /var/log/radvd.log

CREDIT

   The description of the different flags and variables is in large  parts
   taken from RFC 4861.

RFCS

   Narten,  T.,  Nordmark,  E.,  Simpson,  W.,  and  H. Soliman, "Neighbor
   Discovery for IP Version 6 (IPv6)", RFC 4861, September 2007.

   Thomson,  S.,  Narten,  T.,  T.   Jinmei,   "IPv6   Stateless   Address
   Autoconfiguration", RFC 4862, September 2007.

   Deering, S., and R. Hinden, "IP Version 6 Addressing Architecture", RFC
   4291, February 2006.

   Conta, A., Deering, S., and M. Gupta "Internet Control Message Protocol
   (ICMPv6)  for  the Internet Protocol Version 6 (IPv6)", RFC 4443, March
   2006.

   Crawford, M., "Transmission of IPv6 Packets  over  Ethernet  Networks",
   RFC 2464, December 1998.

   Carpenter  B.,  K. Moore, "Connection of IPv6 Domains via IPv4 Clouds",
   RFC 3056, February 2001. (6to4 specification)

   Draves, R., D. Thaler, "Default Router  Preferences  and  More-Specific
   Routes", RFC 4191, November 2005.

   Johnson, D., Perkins, C., and J. Arkko, "Mobility Support in IPv6", RFC
   3775, June 2004.

   Devarapalli, V., Wakikawa, R., Petrescu, A., and  P.  Thubert  "Network
   Mobility (NEMO) Basic Support Protocol", RFC 3963, January 2005.

   J.  Jeong,  S.  Park,  L.  Beloeil,  and  S.  Madanapalli, "IPv6 Router
   Advertisement Options for DNS Configuration", RFC 6106, November 2010.

   Z. Shelby, S. Chakrabarti, E.  Nordmark  and   C.  Bormann  "  Neighbor
   Discovery  Optimization  for IPv6 over Low-Power Wireless Personal Area
   Networks (6LoWPANs)", RFC 6775, November 2012.

SEE ALSO

   radvd(8), radvdump(8)

BUGS

   radvd does not support splitting up RAs to  multiple  packets  (RFC4861
   6.2.3  last  paragraph).   In  practise  this limits advertising to ~45
   prefixes on a link, but there is no reason to be able to so.





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