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IP(8)				     Linux				 IP(8)

       ip - show / manipulate routing, devices, policy routing and tunnels

       ip [ OPTIONS ] OBJECT { COMMAND | help }

       OBJECT := { link | addr | addrlabel | route | rule | neigh | tunnel |
	       maddr | mroute | monitor }

       OPTIONS := { -V[ersion] | -s[tatistics] | -r[esolve] | -f[amily] { inet
	       | inet6 | ipx | dnet | link } | -o[neline] }

       ip link set DEVICE { up | down | arp { on | off } |
	       promisc { on | off } |
	       allmulticast { on | off } |
	       dynamic { on | off } |
	       multicast { on | off } |
	       txqueuelen PACKETS |
	       name NEWNAME |
	       address LLADDR | broadcast LLADDR |
	       mtu MTU |
	       netns PID |
	       alias NAME |
	       vf NUM [ mac LLADDR ] [ vlan VLANID [ qos VLAN-QOS ] ] [ rate
	       TXRATE ]	 }

       ip link show [ DEVICE ]

       ip addr { add | del } IFADDR dev STRING

       ip addr { show | flush } [ dev STRING ] [ scope SCOPE-ID ] [ to PREFIX
	       ] [ FLAG-LIST ] [ label PATTERN ]

       IFADDR := PREFIX | ADDR peer PREFIX [ broadcast ADDR ] [ anycast ADDR ]
	       [ label STRING ] [ scope SCOPE-ID ]

       SCOPE-ID := [ host | link | global | NUMBER ]


       FLAG := [ permanent | dynamic | secondary | primary | tentative | dep‐
	       recated ]

       ip addrlabel { add | del } prefix PREFIX [ dev DEV ] [ label NUMBER ]

       ip addrlabel { list | flush }

       ip route { list | flush } SELECTOR

       ip route get ADDRESS [ from ADDRESS iif STRING  ] [ oif STRING ] [ tos
	       TOS ]

       ip route { add | del | change | append | replace | monitor } ROUTE

       SELECTOR := [ root PREFIX ] [ match PREFIX ] [ exact PREFIX ] [ table
	       TABLE_ID ] [ proto RTPROTO ] [ type TYPE ] [ scope SCOPE ]


       NODE_SPEC := [ TYPE ] PREFIX [ tos TOS ] [ table TABLE_ID ] [ proto
	       RTPROTO ] [ scope SCOPE ] [ metric METRIC ]

       INFO_SPEC := NH OPTIONS FLAGS [ nexthop NH ] ...

       NH := [ via ADDRESS ] [ dev STRING ] [ weight NUMBER ] NHFLAGS

       OPTIONS := FLAGS [ mtu NUMBER ] [ advmss NUMBER ] [ rtt TIME ] [ rttvar
	       TIME ] [ window NUMBER ] [ cwnd NUMBER ] [ initcwnd NUMBER ] [
	       ssthresh REALM ] [ realms REALM ] [ rto_min TIME ] [ initrwnd
	       NUMBER ]

       TYPE := [ unicast | local | broadcast | multicast | throw | unreachable
	       | prohibit | blackhole | nat ]

       TABLE_ID := [ local| main | default | all | NUMBER ]

       SCOPE := [ host | link | global | NUMBER ]

       FLAGS := [ equalize ]

       NHFLAGS := [ onlink | pervasive ]

       RTPROTO := [ kernel | boot | static | NUMBER ]

       ip rule	[ list | add | del | flush ] SELECTOR ACTION

       SELECTOR := [ from PREFIX ] [ to PREFIX ] [ tos TOS ] [ fwmark
	       FWMARK[/MASK] ] [ dev STRING ] [ pref NUMBER ]

       ACTION := [ table TABLE_ID ] [ nat ADDRESS ] [ prohibit | reject |
	       unreachable ] [ realms [SRCREALM/]DSTREALM ]

       TABLE_ID := [ local | main | default | NUMBER ]

       ip neigh { add | del | change | replace } { ADDR [ lladdr LLADDR ] [
	       nud { permanent | noarp | stale | reachable } ] | proxy ADDR }
	       [ dev DEV ]

       ip neigh { show | flush } [ to PREFIX ] [ dev DEV ] [ nud STATE ]

       ip tunnel { add | change | del | show | prl } [ NAME ]
	       [ mode MODE ] [ remote ADDR ] [ local ADDR ]
	       [ [i|o]seq ] [ [i|o]key KEY ] [ [i|o]csum ] ]
	       [ encaplimit ELIM ] [ ttl TTL ]
	       [ tos TOS ] [ flowlabel FLOWLABEL ]
	       [ prl-default ADDR ] [ prl-nodefault ADDR ] [ prl-delete ADDR ]
	       [ [no]pmtudisc ] [ dev PHYS_DEV ] [ dscp inherit ]

       MODE :=	{ ipip | gre | sit | isatap | ip6ip6 | ipip6 | any }

       ADDR := { IP_ADDRESS | any }

       TOS := { NUMBER | inherit }

       ELIM := { none | 0..255 }

       TTL := { 1..255 | inherit }

       KEY := { DOTTED_QUAD | NUMBER }

       TIME := NUMBER[s|ms]

       ip maddr [ add | del ] MULTIADDR dev STRING

       ip maddr show [ dev STRING ]

       ip mroute show [ PREFIX ] [ from PREFIX ] [ iif DEVICE ]

       ip monitor [ all | LISTofOBJECTS ]

       ip xfrm XFRM_OBJECT { COMMAND }

       XFRM_OBJECT := { state | policy | monitor }

       ip xfrm state { add | update } ID [ XFRM_OPT ]  [ mode MODE ]
		[ reqid REQID ]	 [ seq SEQ ]  [ replay-window SIZE ]
		[ flag FLAG-LIST ]  [ encap ENCAP ]  [ sel SELECTOR ]

       ip xfrm state allocspi ID  [ mode MODE ]	 [ reqid REQID ]  [ seq SEQ ]
	       [ min SPI max SPI ]

       ip xfrm state { delete | get } ID

       ip xfrm state { deleteall | list } [ ID ]  [ mode MODE ]
		[ reqid REQID ]	 [ flag FLAG_LIST ]

       ip xfrm state flush [ proto XFRM_PROTO ]

       ip xfrm state count

       ID :=  [ src ADDR ]  [ dst ADDR ]  [ proto XFRM_PROTO ]	[ spi SPI ]

       XFRM_PROTO :=  [ esp | ah | comp | route2 | hao ]

       MODE :=	[ transport | tunnel | ro | beet ] (default=transport)


       FLAG :=	[ noecn | decap-dscp | wildrecv ]


       ENCAP-TYPE := espinudp  | espinudp-nonike

       ALGO-LIST := [ ALGO-LIST ] | [ ALGO ]


       ALGO_TYPE :=  [ enc | auth | comp ]

       SELECTOR := src ADDR[/PLEN] dst ADDR[/PLEN]  [ UPSPEC ]	[ dev DEV ]

       UPSPEC := proto PROTO [[ sport PORT ]  [ dport PORT ] |
		[ type NUMBER ]	 [ code NUMBER ]]

       LIMIT-LIST := [ LIMIT-LIST ] |  [ limit LIMIT ]

       LIMIT :=	 [ [time-soft|time-hard|time-use-soft|time-use-hard] SECONDS ]
	       | [ [byte-soft|byte-hard] SIZE ] |
		[ [packet-soft|packet-hard] COUNT ]

       ip xfrm policy { add | update }	dir DIR SELECTOR [ index INDEX ]
		[ ptype PTYPE ]	 [ action ACTION ]  [ priority PRIORITY ]

       ip xfrm policy { delete | get }	dir DIR [ SELECTOR | index INDEX  ]
		[ ptype PTYPE ]

       ip xfrm policy { deleteall | list }  [ dir DIR ] [ SELECTOR ]
		[ index INDEX ]	 [ action ACTION ]  [ priority PRIORITY ]

       ip xfrm policy flush  [ ptype PTYPE ]

       ip xfrm count

       PTYPE :=	 [ main | sub ] (default=main)

       DIR :=  [ in | out | fwd ]

       SELECTOR := src ADDR[/PLEN] dst ADDR[/PLEN] [ UPSPEC  ] [ dev DEV ]

       UPSPEC := proto PROTO [	[ sport PORT ]	[ dport PORT ] |
		[ type NUMBER ]	 [ code NUMBER ] ]

       ACTION :=  [ allow | block ] (default=allow)

       LIMIT-LIST :=  [ LIMIT-LIST ] |	[ limit LIMIT ]

       LIMIT :=	 [ [time-soft|time-hard|time-use-soft|time-use-hard] SECONDS ]
	       |  [ [byte-soft|byte-hard] SIZE ] |
	       [packet-soft|packet-hard] NUMBER ]

       TMPL-LIST :=  [ TMPL-LIST ] |  [ tmpl TMPL ]

       TMPL := ID [ mode MODE ]	 [ reqid REQID ]  [ level LEVEL ]

       ID :=  [ src ADDR ]  [ dst ADDR ]  [ proto XFRM_PROTO ]	[ spi SPI ]

       XFRM_PROTO :=  [ esp | ah | comp | route2 | hao ]

       MODE :=	[ transport | tunnel | beet ] (default=transport)

       LEVEL :=	 [ required | use ] (default=required)

       ip xfrm monitor [ all | LISTofOBJECTS ]

       ip token { COMMAND | help }

       ip token { set } TOKEN dev DEV

       ip token { get } dev DEV

       ip token { list }

       -V, -Version
	      print the version of the ip utility and exit.

       -s, -stats, -statistics
	      output  more  information.  If the option appears twice or more,
	      the amount of information increases.  As a rule, the information
	      is statistics or some time values.

       -f, -family
	      followed	by  protocol  family  identifier:  inet, inet6 or link
	      ,enforce the protocol family to  use.   If  the  option  is  not
	      present,	the  protocol  family is guessed from other arguments.
	      If the rest of the command line does not give enough information
	      to  guess	 the family, ip falls back to the default one, usually
	      inet or any.  link is a special family identifier	 meaning  that
	      no networking protocol is involved.

       -4     shortcut for -family inet.

       -6     shortcut for -family inet6.

       -0     shortcut for -family link.

       -o, -oneline
	      output  each  record on a single line, replacing line feeds with
	      the '\´ character. This is convenient when  you  want  to	 count
	      records with wc(1)
	       or to grep(1) the output.

       -r, -resolve
	      use  the	system's  name	resolver to print DNS names instead of
	      host addresses.

       link   - network device.

	      - protocol (IP or IPv6) address on a device.

	      - label configuration for protocol address selection.

	      - ARP or NDISC cache entry.

       route  - routing table entry.

       rule   - rule in routing policy database.

	      - multicast address.

       mroute - multicast routing cache entry.

       tunnel - tunnel over IP.

       xfrm   - framework for IPsec protocol.

       The names of all objects may be written in full	or  abbreviated	 form,
       f.e.  address is abbreviated as addr or just a.

       Specifies  the  action  to  perform on the object.  The set of possible
       actions depends on the object type.  As a rule, it is possible to  add,
       delete  and  show (or list ) objects, but some objects do not allow all
       of these operations or have some additional commands.  The help command
       is  available  for all objects.	It prints out a list of available com‐
       mands and argument syntax conventions.

       If no command is given, some default command is assumed.	 Usually it is
       list or, if the objects of this class cannot be listed, help.

ip link - network device configuration
       link  is	 a  network  device and the corresponding commands display and
       change the state of devices.

   ip link set - change device attributes
       dev NAME (default)
	      NAME specifies network device to operate	on.  When  configuring
	      SR-IOV Virtual Fuction (VF) devices, this keyword should specify
	      the associated Physical Function (PF) device.

       up and down
	      change the state of the device to UP or DOWN.

       arp on or arp off
	      change the NOARP flag on the device.

       multicast on or multicast off
	      change the MULTICAST flag on the device.

       dynamic on or dynamic off
	      change the DYNAMIC flag on the device.

       name NAME
	      change the name of the device.  This  operation  is  not	recom‐
	      mended  if  the  device is running or has some addresses already

       txqueuelen NUMBER

       txqlen NUMBER
	      change the transmit queue length of the device.

       mtu NUMBER
	      change the MTU of the device.

       address LLADDRESS
	      change the station address of the interface.

       broadcast LLADDRESS

       brd LLADDRESS

       peer LLADDRESS
	      change the link layer broadcast address or the peer address when
	      the interface is POINTOPOINT.

       netns PID
	      move  the	 device	 to  the network namespace associated with the
	      process PID.

       alias NAME
	      give the device a symbolic name for easy reference.

       vf NUM specify a Virtual Function device to be configured. The  associ‐
	      ated PF device must be specified using the dev parameter.

		      mac LLADDRESS - change the station address for the spec‐
		      ified VF. The vf parameter must be specified.

		      vlan VLANID - change the assigned VLAN for the specified
		      VF. When specified, all traffic sent from the VF will be
		      tagged with the specified VLAN ID. Incoming traffic will
		      be filtered for the specified VLAN ID, and will have all
		      VLAN tags stripped before being passed to the  VF.  Set‐
		      ting  this parameter to 0 disables VLAN tagging and fil‐
		      tering. The vf parameter must be specified.

		      qos VLAN-QOS - assign VLAN QOS (priority) bits  for  the
		      VLAN  tag.  When specified, all VLAN tags transmitted by
		      the VF will include the specified priority bits  in  the
		      VLAN  tag.  If not specified, the value is assumed to be
		      0. Both the vf and vlan parameters  must	be  specified.
		      Setting both vlan and qos as 0 disables VLAN tagging and
		      filtering for the VF.

		      rate TXRATE - change the allowed transmit bandwidth,  in
		      Mbps, for the specified VF.  Setting this parameter to 0
		      disables rate limiting. The vf parameter must be	speci‐

       Warning: If multiple parameter changes are requested, ip aborts immedi‐
       ately after any of the changes have failed.  This is the only case when
       ip  can	move the system to an unpredictable state.  The solution is to
       avoid changing several parameters with one ip link set call.

   ip link show - display device attributes
       dev NAME (default)
	      NAME specifies the network device to show.  If this argument  is
	      omitted all devices are listed.

       up     only display running interfaces.

ip address - protocol address management.
       The  address  is	 a protocol (IP or IPv6) address attached to a network
       device.	Each device must have at least one address to use  the	corre‐
       sponding	 protocol.  It is possible to have several different addresses
       attached to one device.	These addresses are not discriminated, so that
       the  term  alias is not quite appropriate for them and we do not use it
       in this document.

       The ip addr command displays addresses and their properties,  adds  new
       addresses and deletes old ones.

   ip address add - add new protocol address.
       dev NAME
	      the name of the device to add the address to.

       local ADDRESS (default)
	      the  address of the interface. The format of the address depends
	      on the protocol. It is a dotted quad for IP and  a  sequence  of
	      hexadecimal halfwords separated by colons for IPv6.  The ADDRESS
	      may be followed by a slash and a decimal	number	which  encodes
	      the network prefix length.

       peer ADDRESS
	      the  address  of the remote endpoint for pointopoint interfaces.
	      Again, the ADDRESS may be followed by a slash and a decimal num‐
	      ber,  encoding  the network prefix length.  If a peer address is
	      specified, the local address cannot have a prefix	 length.   The
	      network  prefix is associated with the peer rather than with the
	      local address.

       broadcast ADDRESS
	      the broadcast address on the interface.

	      It is possible to use the special symbols '+' and '-' instead of
	      the  broadcast  address.	In this case, the broadcast address is
	      derived by setting/resetting the host bits of the interface pre‐

       label NAME
	      Each  address  may  be  tagged with a label string.  In order to
	      preserve compatibility with Linux-2.0 net aliases,  this	string
	      must  coincide  with  the name of the device or must be prefixed
	      with the device name followed by colon.

       scope SCOPE_VALUE
	      the scope of the area where this address is valid.   The	avail‐
	      able  scopes are listed in file /etc/iproute2/rt_scopes.	Prede‐
	      fined scope values are:

		      global - the address is globally valid.

		      site - (IPv6 only) the address is site local, i.e. it is
		      valid inside this site.

		      link  - the address is link local, i.e. it is valid only
		      on this device.

		      host - the address is valid only inside this host.

   ip address delete - delete protocol address
       Arguments: coincide with the arguments of ip addr add.  The device name
       is  a  required	argument.  The rest are optional.  If no arguments are
       given, the first address is deleted.

   ip address show - look at protocol addresses
       dev NAME (default)
	      name of device.

       scope SCOPE_VAL
	      only list addresses with this scope.

       to PREFIX
	      only list addresses matching this prefix.

       label PATTERN
	      only list addresses with labels matching the  PATTERN.   PATTERN
	      is a usual shell style pattern.

       dynamic and permanent
	      (IPv6  only)  only  list	addresses  installed  due to stateless
	      address configuration  or	 only  list  permanent	(not  dynamic)

	      (IPv6  only)  only  list	addresses which did not pass duplicate
	      address detection.

	      (IPv6 only) only list deprecated addresses.

       primary and secondary
	      only list primary (or secondary) addresses.

   ip address flush - flush protocol addresses
       This command flushes the protocol addresses selected by some criteria.

       This command has the same arguments as show.  The difference is that it
       does not run when no arguments are given.

       Warning:	 This  command	(and  other flush commands described below) is
       pretty dangerous.  If you make a mistake, it will not forgive  it,  but
       will cruelly purge all the addresses.

       With the -statistics option, the command becomes verbose. It prints out
       the number of deleted addresses and the number of rounds made to	 flush
       the  address  list.   If this option is given twice, ip addr flush also
       dumps all the deleted addresses in the format described in the previous

ip addrlabel - protocol address label management.
       IPv6 address label is used for address selection described in RFC 3484.
       Precedence is managed by userspace, and only label is stored in kernel.

   ip addrlabel add - add an address label
       the command adds an address label entry to the kernel.

       prefix PREFIX

       dev DEV
	      the outgoing interface.

       label NUMBER
	      the label for the prefix.	 0xffffffff is reserved.

   ip addrlabel del - delete an address label
       the command deletes an address label entry in the  kernel.   Arguments:
       coincide	 with  the  arguments  of  ip  addrlabel  add but label is not

   ip addrlabel list - list address labels
       the command show contents of address labels.

   ip addrlabel flush - flush address labels
       the command flushes the contents of address  labels  and	 it  does  not
       restore default settings.

ip neighbour - neighbour/arp tables management.
       neighbour  objects  establish  bindings	between protocol addresses and
       link layer addresses  for  hosts	 sharing  the  same  link.   Neighbour
       entries are organized into tables. The IPv4 neighbour table is known by
       another name - the ARP table.

       The corresponding commands display neighbour bindings and their proper‐
       ties, add new neighbour entries and delete old ones.

   ip neighbour add - add a new neighbour entry
   ip neighbour change - change an existing entry
   ip neighbour replace - add a new entry or change an existing one
       These commands create new neighbour records or update existing ones.

       to ADDRESS (default)
	      the  protocol  address of the neighbour. It is either an IPv4 or
	      IPv6 address.

       dev NAME
	      the interface to which this neighbour is attached.

       lladdr LLADDRESS
	      the link layer address of the neighbour.	LLADDRESS can also  be

       nud NUD_STATE
	      the  state  of  the neighbour entry.  nud is an abbreviation for
	      'Neigh bour Unreachability Detection'.  The state can  take  one
	      of the following values:

		      permanent - the neighbour entry is valid forever and can
		      be only be removed administratively.

		      noarp - the neighbour entry is  valid.  No  attempts  to
		      validate	this  entry will be made but it can be removed
		      when its lifetime expires.

		      reachable - the  neighbour  entry	 is  valid  until  the
		      reachability timeout expires.

		      stale  -	the  neighbour	entry is valid but suspicious.
		      This option to ip neigh does not	change	the  neighbour
		      state  if it was valid and the address is not changed by
		      this command.

   ip neighbour delete - delete a neighbour entry
       This command invalidates a neighbour entry.

       The arguments are the same as with ip neigh add, except that lladdr and
       nud are ignored.

       Warning: Attempts to delete or manually change a noarp entry created by
       the kernel may result in unpredictable  behaviour.   Particularly,  the
       kernel  may try to resolve this address even on a NOARP interface or if
       the address is multicast or broadcast.

   ip neighbour show - list neighbour entries
       This commands displays neighbour tables.

       to ADDRESS (default)
	      the prefix selecting the neighbours to list.

       dev NAME
	      only list the neighbours attached to this device.

       unused only list neighbours which are not currently in use.

       nud NUD_STATE
	      only list neighbour entries in this state.  NUD_STATE takes val‐
	      ues  listed  below  or  the  special  value  all which means all
	      states.  This option may occur more than once.  If  this	option
	      is absent, ip lists all entries except for none and noarp.

   ip neighbour flush - flush neighbour entries
       This  command  flushes  neighbour tables, selecting entries to flush by
       some criteria.

       This command has the same arguments as show.  The differences are  that
       it  does	 not  run  when	 no  arguments are given, and that the default
       neighbour states to be flushed do not include permanent and noarp.

       With the -statistics option, the command becomes	 verbose.   It	prints
       out  the	 number of deleted neighbours and the number of rounds made to
       flush the neighbour table.  If the option  is  given  twice,  ip	 neigh
       flush also dumps all the deleted neighbours.

ip route - routing table management
       Manipulate  route entries in the kernel routing tables keep information
       about paths to other networked nodes.

       Route types:

	       unicast - the route entry describes real paths to the  destina‐
	       tions covered by the route prefix.

	       unreachable  - these destinations are unreachable.  Packets are
	       discarded and the ICMP message host unreachable	is  generated.
	       The local senders get an EHOSTUNREACH error.

	       blackhole  -  these  destinations are unreachable.  Packets are
	       discarded silently.  The local senders get an EINVAL error.

	       prohibit - these destinations  are  unreachable.	  Packets  are
	       discarded  and  the ICMP message communication administratively
	       prohibited is generated.	  The  local  senders  get  an	EACCES

	       local  - the destinations are assigned to this host.  The pack‐
	       ets are looped back and delivered locally.

	       broadcast - the	destinations  are  broadcast  addresses.   The
	       packets are sent as link broadcasts.

	       throw  -	 a  special  control  route  used together with policy
	       rules. If such a route is selected, lookup  in  this  table  is
	       terminated  pretending that no route was found.	Without policy
	       routing it is equivalent to the absence of  the	route  in  the
	       routing	table.	 The  packets are dropped and the ICMP message
	       net unreachable is generated.  The local senders get an ENETUN‐
	       REACH error.

	       nat  - a special NAT route.  Destinations covered by the prefix
	       are considered  to  be  dummy  (or  external)  addresses	 which
	       require	translation to real (or internal) ones before forward‐
	       ing.  The addresses to  translate  to  are  selected  with  the
	       attribute  Warning:  Route  NAT is no longer supported in Linux


	       anycast	-  not	implemented  the  destinations	 are   anycast
	       addresses assigned to this host.	 They are mainly equivalent to
	       local with one difference: such addresses are invalid when used
	       as the source address of any packet.

	       multicast  -  a special type used for multicast routing.	 It is
	       not present in normal routing tables.

       Route tables: Linux-2.x can pack routes	into  several  routing	tables
       identified  by  a number in the range from 1 to 255 or by name from the
       file /etc/iproute2/rt_tables By default all normal routes are  inserted
       into  the  main table (ID 254) and the kernel only uses this table when
       calculating routes.

       Actually, one other table always exists, which is  invisible  but  even
       more  important.	  It is the local table (ID 255).  This table consists
       of routes for local and broadcast addresses.  The kernel maintains this
       table automatically and the administrator usually need not modify it or
       even look at it.

       The multiple routing tables enter the game when policy routing is used.

   ip route add - add new route
   ip route change - change route
   ip route replace - change or add new one
       to TYPE PREFIX (default)
	      the destination prefix of the route.  If	TYPE  is  omitted,  ip
	      assumes  type  unicast.	Other values of TYPE are listed above.
	      PREFIX is an IP or IPv6 address optionally followed by  a	 slash
	      and  the prefix length.  If the length of the prefix is missing,
	      ip assumes a full-length host route.  There is  also  a  special
	      PREFIX default - which is equivalent to IP 0/0 or to IPv6 ::/0.

       tos TOS

       dsfield TOS
	      the  Type Of Service (TOS) key.  This key has no associated mask
	      and the longest match is understood as: First, compare  the  TOS
	      of the route and of the packet.  If they are not equal, then the
	      packet may still match a route with a zero TOS.  TOS  is	either
	      an   8   bit   hexadecimal   number   or	 an   identifier  from

       metric NUMBER

       preference NUMBER
	      the preference value of the route.  NUMBER is an arbitrary 32bit

       table TABLEID
	      the  table  to  add this route to.  TABLEID may be a number or a
	      string from the file /etc/iproute2/rt_tables.  If this parameter
	      is  omitted,  ip	assumes	 the main table, with the exception of
	      local , broadcast and nat routes, which are put into  the	 local
	      table by default.

       dev NAME
	      the output device name.

       via ADDRESS
	      the  address of the nexthop router.  Actually, the sense of this
	      field depends on the route type.	For normal unicast  routes  it
	      is  either  the true next hop router or, if it is a direct route
	      installed in BSD compatibility mode, it can be a	local  address
	      of the interface.	 For NAT routes it is the first address of the
	      block of translated IP destinations.

       src ADDRESS
	      the source address to prefer when sending	 to  the  destinations
	      covered by the route prefix.

       realm REALMID
	      the  realm  to  which  this route is assigned.  REALMID may be a
	      number or a string from the file /etc/iproute2/rt_realms.

       mtu MTU

       mtu lock MTU
	      the MTU along the path to the destination.  If the modifier lock
	      is  not  used,  the MTU may be updated by the kernel due to Path
	      MTU Discovery.  If the modifier lock is used, no path  MTU  dis‐
	      covery  will  be	tried, all packets will be sent without the DF
	      bit in IPv4 case or fragmented to MTU for IPv6.

       window NUMBER
	      the maximal window for TCP to advertise to  these	 destinations,
	      measured	in  bytes.  It limits maximal data bursts that our TCP
	      peers are allowed to send to us.

       rtt TIME
	      the initial RTT ('Round Trip Time') estimate. If	no  suffix  is
	      specified	 the units are raw values passed directly to the rout‐
	      ing code to maintain compatability with previous releases.  Oth‐
	      erwise  if a suffix of s, sec or secs is used to specify seconds
	      and ms, msec or msecs to specify milliseconds.

       rttvar TIME (2.3.15+ only)
	      the initial RTT variance estimate. Values are specified as  with
	      rtt above.

       rto_min TIME (2.6.23+ only)
	      the minimum TCP Retransmission TimeOut to use when communicating
	      with this destination.  Values are specified as with rtt above.

       ssthresh NUMBER (2.3.15+ only)
	      an estimate for the initial slow start threshold.

       cwnd NUMBER (2.3.15+ only)
	      the clamp for congestion window.	It is ignored if the lock flag
	      is not used.

       initcwnd NUMBER
	      the  maximum  initial  congestion window (cwnd) size in MSS of a
	      TCP connection.

       initrwnd NUMBER (2.6.33+ only)
	      the initial receive window size for connections to this destina‐
	      tion.  Actual window size is this value multiplied by the MSS of
	      the connection.  The default value is zero, meaning to use  Slow
	      Start value.

       advmss NUMBER (2.3.15+ only)
	      the  MSS ('Maximal Segment Size') to advertise to these destina‐
	      tions when establishing TCP connections.	If it  is  not	given,
	      Linux  uses a default value calculated from the first hop device
	      MTU.  (If the path to  these  destination	 is  asymmetric,  this
	      guess may be wrong.)

       reordering NUMBER (2.3.15+ only)
	      Maximal  reordering  on  the path to this destination.  If it is
	      not given, Linux uses the value selected	with  sysctl  variable

       nexthop NEXTHOP
	      the  nexthop  of	a multipath route.  NEXTHOP is a complex value
	      with its own syntax similar to the top level argument lists:

		      via ADDRESS - is the nexthop router.

		      dev NAME - is the output device.

		      weight NUMBER - is a weight for this element of a multi‐
		      path route reflecting its relative bandwidth or quality.

       scope SCOPE_VAL
	      the  scope  of  the  destinations	 covered  by the route prefix.
	      SCOPE_VAL	 may  be  a  number  or	 a  string   from   the	  file
	      /etc/iproute2/rt_scopes.	 If  this  parameter  is  omitted,  ip
	      assumes scope global for all  gatewayed  unicast	routes,	 scope
	      link  for direct unicast and broadcast routes and scope host for
	      local routes.

       protocol RTPROTO
	      the routing protocol identifier of this route.  RTPROTO may be a
	      number  or  a  string from the file /etc/iproute2/rt_protos.  If
	      the routing protocol ID is not given, ip assumes	protocol  boot
	      (i.e.  it	 assumes  the  route  was added by someone who doesn't
	      understand what they are doing).	Several protocol values have a
	      fixed interpretation.  Namely:

		      redirect	- the route was installed due to an ICMP redi‐

		      kernel - the route was installed by  the	kernel	during

		      boot  -  the  route  was	installed  during  the	bootup
		      sequence.	 If a routing daemon starts, it will purge all
		      of them.

		      static - the route was installed by the administrator to
		      override dynamic routing. Routing	 daemon	 will  respect
		      them and, probably, even advertise them to its peers.

		      ra  - the route was installed by Router Discovery proto‐

	      The rest of the values are not reserved and the administrator is
	      free to assign (or not to assign) protocol tags.

       onlink pretend that the nexthop is directly attached to this link, even
	      if it does not match any interface prefix.

	      allow packet by packet randomization on multipath routes.	 With‐
	      out this modifier, the route will be frozen to one selected nex‐
	      thop, so that load splitting will only occur on  per-flow	 base.
	      equalize only works if the kernel is patched.

   ip route delete - delete route
       ip  route  del has the same arguments as ip route add, but their seman‐
       tics are a bit different.

       Key values (to, tos, preference and table) select the route to  delete.
       If optional attributes are present, ip verifies that they coincide with
       the attributes of the route to delete.  If no route with the given  key
       and attributes was found, ip route del fails.

   ip route show - list routes
       the command displays the contents of the routing tables or the route(s)
       selected by some criteria.

       to SELECTOR (default)
	      only select routes from the given range of destinations.	SELEC‐
	      TOR  consists of an optional modifier (root, match or exact) and
	      a prefix.	 root PREFIX selects routes with prefixes not  shorter
	      than  PREFIX.   F.e.  root 0/0 selects the entire routing table.
	      match PREFIX selects routes with prefixes not longer  than  PRE‐
	      FIX.   F.e.  match 10.0/16 selects 10.0/16, 10/8 and 0/0, but it
	      does not select 10.1/16 and 10.0.0/24.   And  exact  PREFIX  (or
	      just  PREFIX)  selects routes with this exact prefix. If neither
	      of these options are present, ip assumes root 0/0 i.e. it	 lists
	      the entire table.

       tos TOS
	      dsfield TOS only select routes with the given TOS.

       table TABLEID
	      show  the	 routes from this table(s).  The default setting is to
	      show tablemain.  TABLEID may either be the ID of a real table or
	      one of the special values:

		      all - list all of the tables.

		      cache - dump the routing cache.


       cached list  cloned  routes  i.e.  routes which were dynamically forked
	      from other routes because some route attribute  (f.e.  MTU)  was
	      updated.	Actually, it is equivalent to table cache.

       from SELECTOR
	      the same syntax as for to, but it binds the source address range
	      rather than destinations.	 Note that the from option only	 works
	      with cloned routes.

       protocol RTPROTO
	      only list routes of this protocol.

       scope SCOPE_VAL
	      only list routes with this scope.

       type TYPE
	      only list routes of this type.

       dev NAME
	      only list routes going via this device.

       via PREFIX
	      only  list routes going via the nexthop routers selected by PRE‐

       src PREFIX
	      only list routes with preferred  source  addresses  selected  by

       realm REALMID

	      only list routes with these realms.

   ip route flush - flush routing tables
       this command flushes routes selected by some criteria.

       The arguments have the same syntax and semantics as the arguments of ip
       route show, but routing tables are not listed  but  purged.   The  only
       difference  is  the  default action: show dumps all the IP main routing
       table but flush prints the helper page.

       With the -statistics option, the command becomes verbose. It prints out
       the number of deleted routes and the number of rounds made to flush the
       routing table. If the option is given twice, ip route flush also	 dumps
       all  the deleted routes in the format described in the previous subsec‐

   ip route get - get a single route
       this command gets a single route to a destination and prints  its  con‐
       tents exactly as the kernel sees it.

       to ADDRESS (default)
	      the destination address.

       from ADDRESS
	      the source address.

       tos TOS

       dsfield TOS
	      the Type Of Service.

       iif NAME
	      the device from which this packet is expected to arrive.

       oif NAME
	      force the output device on which this packet will be routed.

	      if no source address (option from) was given, relookup the route
	      with the source set to the preferred address received  from  the
	      first  lookup.  If policy routing is used, it may be a different

       Note that this operation is not equivalent  to  ip  route  show.	  show
       shows  existing	routes.	  get  resolves them and creates new clones if
       necessary.  Essentially, get is equivalent to sending  a	 packet	 along
       this  path.   If	 the  iif  argument is not given, the kernel creates a
       route to output packets towards the  requested  destination.   This  is
       equivalent  to  pinging	the  destination with a subsequent ip route ls
       cache, however, no packets are actually sent.  With the	iif  argument,
       the  kernel  pretends  that  a  packet  arrived from this interface and
       searches for a path to forward the packet.

ip rule - routing policy database management
       Rules in the routing policy database control the route selection	 algo‐

       Classic	routing algorithms used in the Internet make routing decisions
       based only on the destination address of packets (and  in  theory,  but
       not in practice, on the TOS field).

       In  some	 circumstances	we want to route packets differently depending
       not only on destination addresses, but also  on	other  packet  fields:
       source  address,	 IP  protocol, transport protocol ports or even packet
       payload.	 This task is called 'policy routing'.

       To solve this task, the conventional destination based  routing	table,
       ordered	according to the longest match rule, is replaced with a 'rout‐
       ing policy database' (or RPDB), which selects routes by executing  some
       set of rules.

       Each  policy  routing  rule consists of a selector and an action predi‐
       cate.  The RPDB is scanned in the order	of  increasing	priority.  The
       selector	 of  each  rule	 is  applied  to  {source address, destination
       address, incoming interface, tos, fwmark} and, if the selector  matches
       the  packet,  the action is performed.  The action predicate may return
       with success.  In this case, it will either give	 a  route  or  failure
       indication  and the RPDB lookup is terminated. Otherwise, the RPDB pro‐
       gram continues on the next rule.

       Semantically, natural action is to select the nexthop  and  the	output

       At  startup  time  the kernel configures the default RPDB consisting of
       three rules:

       1.     Priority: 0, Selector: match anything,  Action:  lookup  routing
	      table  local (ID 255).  The local table is a special routing ta‐
	      ble containing high priority control routes for local and broad‐
	      cast addresses.

	      Rule 0 is special. It cannot be deleted or overridden.

       2.     Priority:	 32766, Selector: match anything, Action: lookup rout‐
	      ing table main (ID 254).	The main table is the  normal  routing
	      table containing all non-policy routes. This rule may be deleted
	      and/or overridden with other ones by the administrator.

       3.     Priority: 32767, Selector: match anything, Action: lookup	 rout‐
	      ing  table default (ID 253).  The default table is empty.	 It is
	      reserved for some post-processing if no previous	default	 rules
	      selected the packet.  This rule may also be deleted.

       Each  RPDB  entry  has  additional  attributes.	 F.e.  each rule has a
       pointer to some routing table.  NAT  and	 masquerading  rules  have  an
       attribute  to  select  new IP address to translate/masquerade.  Besides
       that, rules have some optional attributes, which	 routes	 have,	namely
       realms.	 These	values	do not override those contained in the routing
       tables.	They are only used if the route did not select any attributes.

       The RPDB may contain rules of the following types:

	       unicast - the rule prescribes to return the route found in  the
	       routing table referenced by the rule.

	       blackhole - the rule prescribes to silently drop the packet.

	       unreachable  -  the  rule  prescribes to generate a 'Network is
	       unreachable' error.

	       prohibit - the rule prescribes to  generate  'Communication  is
	       administratively prohibited' error.

	       nat  -  the  rule prescribes to translate the source address of
	       the IP packet into some other value.

   ip rule add - insert a new rule
   ip rule delete - delete a rule
       type TYPE (default)
	      the type of this rule.  The list of valid types was given in the
	      previous subsection.

       from PREFIX
	      select the source prefix to match.

       to PREFIX
	      select the destination prefix to match.

       iif NAME
	      select  the incoming device to match.  If the interface is loop‐
	      back, the rule only matches packets originating from this	 host.
	      This  means that you may create separate routing tables for for‐
	      warded and local packets and, hence, completely segregate them.

       tos TOS

       dsfield TOS
	      select the TOS value to match.

       fwmark MARK
	      select the fwmark value to match.

       priority PREFERENCE
	      the priority of this rule.  Each rule should have an  explicitly
	      set unique priority value.  The options preference and order are
	      synonyms with priority.

       table TABLEID
	      the routing table identifier to  lookup  if  the	rule  selector
	      matches.	It is also possible to use lookup instead of table.

       realms FROM/TO
	      Realms  to  select  if  the  rule	 matched and the routing table
	      lookup succeeded.	 Realm TO is only used if the  route  did  not
	      select any realm.

       nat ADDRESS
	      The  base	 of  the  IP  address  block  to translate (for source
	      addresses).  The ADDRESS may be either the start of the block of
	      NAT  addresses  (selected by NAT routes) or a local host address
	      (or even zero).  In the last case the router does not  translate
	      the packets, but masquerades them to this address.  Using map-to
	      instead of nat means the same thing.

	      Warning: Changes to the RPDB made with  these  commands  do  not
	      become  active  immediately.   It is assumed that after a script
	      finishes a batch of updates, it flushes the routing  cache  with
	      ip route flush cache.

   ip rule flush - also dumps all the deleted rules.
       This command has no arguments.

   ip rule show - list rules
       This  command  has  no arguments.  The options list or lst are synonyms
       with show.

ip maddress - multicast addresses management
       maddress objects are multicast addresses.

   ip maddress show - list multicast addresses
       dev NAME (default)
	      the device name.

   ip maddress add - add a multicast address
   ip maddress delete - delete a multicast address
       these commands attach/detach a static link layer multicast  address  to
       listen  on  the interface.  Note that it is impossible to join protocol
       multicast groups statically.  This  command  only  manages  link	 layer

       address LLADDRESS (default)
	      the link layer multicast address.

       dev NAME
	      the device to join/leave this multicast address.

ip mroute - multicast routing cache management
       mroute  objects	are  multicast routing cache entries created by a user
       level mrouting daemon (f.e.  pimd or mrouted ).

       Due to the limitations of the current interface to the multicast	 rout‐
       ing engine, it is impossible to change mroute objects administratively,
       so we may only display them.  This limitation will be  removed  in  the

   ip mroute show - list mroute cache entries
       to PREFIX (default)
	      the  prefix  selecting  the  destination	multicast addresses to

       iif NAME
	      the interface on which multicast packets are received.

       from PREFIX
	      the prefix selecting the IP source addresses  of	the  multicast

ip tunnel - tunnel configuration
       tunnel  objects	are  tunnels,  encapsulating packets in IP packets and
       then sending them over the IP  infrastructure.	The  encapulating  (or
       outer)  address	family	is specified by the -f option.	The default is

   ip tunnel add - add a new tunnel
   ip tunnel change - change an existing tunnel
   ip tunnel delete - destroy a tunnel
       name NAME (default)
	      select the tunnel device name.

       mode MODE
	      set the tunnel mode. Available modes depend on the encapsulating
	      address family.
	      Modes  for  IPv4	encapsulation available: ipip, sit, isatap and
	      Modes for IPv6 encapsulation available: ip6ip6, ipip6 and any.

       remote ADDRESS
	      set the remote endpoint of the tunnel.

       local ADDRESS
	      set the fixed local address for tunneled packets.	 It must be an
	      address on another interface of this host.

       ttl N  set  a  fixed  TTL  N on tunneled packets.  N is a number in the
	      range 1--255. 0 is a special value meaning that packets  inherit
	      the  TTL value.  The default value for IPv4 tunnels is: inherit.
	      The default value for IPv6 tunnels is: 64.

       tos T

       dsfield T

       tclass T
	      set a fixed TOS (or traffic class in IPv6) T on  tunneled	 pack‐
	      ets.  The default value is: inherit.

       dev NAME
	      bind the tunnel to the device NAME so that tunneled packets will
	      only be routed via this device and will not be able to escape to
	      another device when the route to endpoint changes.

	      disable  Path  MTU  Discovery  on this tunnel.  It is enabled by
	      default.	Note that  a  fixed  ttl  is  incompatible  with  this
	      option: tunnelling with a fixed ttl always makes pmtu discovery.

       key K

       ikey K

       okey K (	 only  GRE  tunnels  ) use keyed GRE with key K. K is either a
	      number or an IP address-like dotted  quad.   The	key  parameter
	      sets  the	 key  to  use  in  both directions.  The ikey and okey
	      parameters set different keys for input and output.

       csum, icsum, ocsum
	      ( only GRE tunnels )  generate/require  checksums	 for  tunneled
	      packets.	The ocsum flag calculates checksums for outgoing pack‐
	      ets.  The icsum flag requires that all input  packets  have  the
	      correct  checksum.   The csum flag is equivalent to the combina‐
	      tion icsum ocsum.

       seq, iseq, oseq
	      ( only GRE tunnels ) serialize packets.  The oseq	 flag  enables
	      sequencing of outgoing packets.  The iseq flag requires that all
	      input packets are serialized.  The seq flag is equivalent to the
	      combination iseq oseq.  It isn't work. Don't use it.

       dscp inherit
	      (	 only  IPv6 tunnels ) Inherit DS field between inner and outer

       encaplim ELIM
	      ( only IPv6 tunnels ) set a fixed encapsulation limit.   Default
	      is 4.

       flowlabel FLOWLABEL
	      ( only IPv6 tunnels ) set a fixed flowlabel.

   ip tunnel prl - potential router list (ISATAP only)
       dev NAME
	      mandatory device name.

       prl-default ADDR

       prl-nodefault ADDR

       prl-delete ADDR
	      Add or delete ADDR as a potential router or default router.

   ip tunnel show - list tunnels
       This command has no arguments.

ip monitor and rtmon - state monitoring
       The  ip	utility can monitor the state of devices, addresses and routes
       continuously.  This option has a slightly  different  format.   Namely,
       the  monitor  command  is  the  first  in the command line and then the
       object list follows:

       ip monitor [ all | LISTofOBJECTS ]

       OBJECT-LIST is the list of object types that we want  to	 monitor.   It
       may  contain link, address and route.  If no file argument is given, ip
       opens RTNETLINK, listens on it and dumps state changes  in  the	format
       described in previous sections.

       If a file name is given, it does not listen on RTNETLINK, but opens the
       file containing RTNETLINK messages saved in  binary  format  and	 dumps
       them.   Such  a	history	 file can be generated with the rtmon utility.
       This utility has a command line syntax similar to ip monitor.  Ideally,
       rtmon  should be started before the first network configuration command
       is issued. F.e. if you insert:

	       rtmon file /var/log/rtmon.log

       in a startup script, you will be able to view the full history later.

       Certainly, it is possible to start rtmon at any time.  It prepends  the
       history with the state snapshot dumped at the moment of starting.

ip xfrm - setting xfrm
       xfrm is an IP framework, which can transform format of the datagrams,
       i.e.  encrypt  the  packets  with  some algorithm. xfrm policy and xfrm
       state are associated through templates TMPL_LIST.   This	 framework  is
       used as a part of IPsec protocol.

   ip xfrm state add - add new state into xfrm
   ip xfrm state update - update existing xfrm state
   ip xfrm state allocspi - allocate SPI value
       MODE   is set as default to transport, but it could be set to tunnel,ro
	      or beet.

	      contains one or more flags.

       FLAG   could be set to noecn, decap-dscp or wildrecv.

       ENCAP  encapsulation is set to encapsulation  type  ENCAP-TYPE,	source
	      port SPORT, destination port DPORT and OADDR.

	      could be set to espinudp or espinudp-nonike.

	      contains one or more algorithms ALGO which depend on the type of
	      algorithm set by ALGO_TYPE.  It can be used these algoritms enc,
	      auth or comp.

   ip xfrm policy add - add a new policy
   ip xfrm policy update - update an existing policy
   ip xfrm policy delete - delete existing policy
   ip xfrm policy get - get existing policy
   ip xfrm policy deleteall - delete all existing xfrm policy
   ip xfrm policy list - print out the list of xfrm policy
   ip xfrm policy flush - flush policies
       It can be flush all policies or only those specified with ptype.

       dir DIR
	      directory could be one of these: inp, out or fwd.

	      selects  for  which  addresses  will  be	set up the policy. The
	      selector is defined by source and destination address.

       UPSPEC is defined by source port sport, destination port dport, type as
	      number and code also number.

       dev DEV
	      specify network device.

       index INDEX
	      the number of indexed policy.

       ptype PTYPE
	      type is set as default on main, could be switch on sub.

       action ACTION
	      is set as default on allow.  It could be switch on block.

       priority PRIORITY
	      priority is a number. Default priority is set on zero.

	      limits are set in seconds, bytes or numbers of packets.

	      template list is based on ID, mode, reqid and level.

       ID     is  specified  by source address, destination address, proto and
	      value of spi.

	      values: esp, ah, comp, route2 or hao.

       MODE   is set as default on transport, but it could be set on tunnel or

       LEVEL  is set as default on required and the other choice is use.

       UPSPEC is specified by sport, dport, type and code (NUMBER).

   ip xfrm monitor - is used for listing all objects or defined group of them.
       The  xfrm  monitor  can monitor the policies for all objects or defined
       group of them.

ip token
       IPv6 tokenized interface identifer support is used for assigning	 well-
       known host-part addresses to nodes whilst still obtaining a global net‐
       work prefix from Router advertisements. The  primary  target  for  tok‐
       enized  identifiers  are	 server	 platforms where addresses are usually
       manually configured, rather than using DHCPv6 or SLAAC. By  using  tok‐
       enized  identifiers,  hosts can still determine their network prefix by
       use of SLAAC, but more readily be automatically renumbered should their
       network	prefix change [1]. Tokenized IPv6 Identifiers are described in
       the draft [1]: <draft-chown-6man-tokenised-ipv6-identifiers-02>.

   ip token set - set an interface token
       set the interface token to the kernel. Once a token is set,  it	cannot
       be removed from the interface, only overwritten.

       TOKEN  the interface identifer token address.

       dev DEV
	      the networking interface.

   ip token get - get the interface token from the kernel
       show a tokenized interface identifer of a particular networking device.
       Arguments: coincide with the arguments of ip token set  but  the	 TOKEN
       must be left out.

   ip token list - list all interface tokens
       list  all  tokenized interface identifers for the networking interfaces
       from the kernel.

       ip was written by Alexey N. Kuznetsov and added in Linux 2.2.

       IP Command reference ip-cref.ps
       IP tunnels ip-cref.ps
       User documentation at http://lartc.org/, but please  direct  bugreports
       and patches to: <netdev@vger.kernel.org>

       Original Manpage	 by Michail Litvak <mci@owl.openwall.com>

iproute2			17 January 2002				 IP(8)

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