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Linux 2.6 - man page for ip (linux section 8)

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 add link DEVICE [ name ] NAME
	       [ txqueuelen PACKETS ]
	       [ address LLADDR ] [ broadcast LLADDR ]
	       [ mtu MTU ]
	       type TYPE [ ARGS ]

       TYPE := [ vlan | maclan | can ]

       ip link delete DEVICE type TYPE [ ARGS ]

       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 | deprecated | dadfailed |
	       temporary ]

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

       ip addrlabel { list | flush }

       ip route { list | flush } SELECTOR

       ip route save SELECTOR

       ip route restore

       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 ] [ ssthresh REALM ] [ realms REALM ] [ rto_min TIME ] [
	       initcwnd NUMBER ] [ initrwnd NUMBER ]

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

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

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

       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] ] [ iif
	       STRING ] [ oif STRING ] [ pref NUMBER ]

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

       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 ] |
		[ key KEY ]]

       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 ] |
		[ key KEY ] ]

       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 ]

       -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 infor-
	      mation increases.  As a rule, the information is statistics or some time values.

       -l, -loops
	      Specify maximum number of loops the 'ip addr flush' logic will attempt before  giv-
	      ing up.  The default is 10.  Zero (0) means loop until all addresses are removed.

       -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 commands 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

   ip link add - add virtual link
       link DEVICE
	      specifies the physical device to act operate on.

	      NAME specifies the name of the new virtual device.

	      TYPE specifies the type of the new device.

	      Link types:

		      vlan - 802.1q tagged virrtual LAN interface

		      macvlan - virtual interface base on link layer address (MAC)

		      can - Controller Area Network interface

   ip link delete - delete virtual link
       DEVICE  specifies  the  virtual	device to act operate on.  TYPE specifies the type of the

       dev DEVICE
	      specifies the physical device to act operate on.

   ip link set - change device attributes
       dev DEVICE
	      DEVICE specifies network device to operate on. When configuring SR-IOV Virtual Fuc-
	      tion  (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 recommended if the device  is
	      running or has some addresses already configured.

       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

       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 associated PF  device  must
	      be specified using the dev parameter.

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

		      vlan VLANID - change the assigned VLAN for the specified	VF.  When  speci-
		      fied,  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. Setting this
		      parameter to 0 disables VLAN tagging and filtering. The vf  parameter  must
		      be specified.

		      qos VLAN-QOS - assign VLAN QOS (priority) bits for the VLAN tag. When spec-
		      ified, all VLAN tags transmitted by the VF will include the specified  pri-
		      ority 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 spec-
		      ified VF.  Setting this parameter to  0  disables  rate  limiting.  The  vf
		      parameter must be specified.

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

   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 corresponding protocol.  It is possible to  have
       several	different  addresses  attached	to one device.	These addresses are not discrimi-
       nated, 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  number,  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

       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 prefix.

       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 available scopes are listed
	      in file /etc/iproute2/rt_scopes.	Predefined scope values are:

		      global - the address is globally valid.

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

		      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

   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) addresses.

	      (IPv6  only) only list addresses which have not yet passed duplicate address detec-

	      (IPv6 only) only list deprecated addresses.

	      (IPv6 only) only list addresses which have failed duplicate address detection.

	      (IPv6 only) only list temporary 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 subsection.

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 required.

   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 set-

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 properties, add new neigh-
       bour 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 null.

       nud NUD_STATE
	      the  state of the neighbour entry.  nud is an abbreviation for 'Neighbour Unreacha-
	      bility Detection'.  The state can take one of the following values:

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

		      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

		      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 values 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 destinations 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

	       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 error.

	       local - the destinations are assigned to this host.  The packets 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 ENETUNREACH 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 forwarding.	The addresses to  translate  to  are  selected	with  the
	       attribute Warning: Route NAT is no longer supported in Linux 2.6.


	       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 nor-
	       mal routing tables.

       Route tables: Linux-2.x can pack routes into several routing tables identified by a number
       in  the	range  from 1 to 2^31 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.  Values (0, 253, 254, and 255) are reserved for built-in

       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 number.

       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

       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 discovery 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 routing code to maintain compatibility with
	      previous releases.  Otherwise if a suffix of s, sec or secs is used to specify sec-
	      onds 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 destina-
	      tion.  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 (2.5.70+ only)
	      the initial congestion window size for connections  to  this  destination.   Actual
	      window size is this value multiplied by the MSS (``Maximal Segment Size'') for same
	      connection. The default is zero, meaning to use the values specified in RFC2414.

       initrwnd NUMBER (2.6.33+ only)
	      the initial receive window size for connections to this destination.  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 destinations when establish-
	      ing  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 net/ipv4/tcp_reordering.

       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 multipath route reflect-
		      ing its relative bandwidth or quality.

       scope SCOPE_VAL
	      the scope of the destinations covered by the route prefix.  SCOPE_VAL may be a num-
	      ber  or a string from the file /etc/iproute2/rt_scopes.  If this parameter is omit-
	      ted, 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  interpreta-
	      tion.  Namely:

		      redirect - the route was installed due to an ICMP redirect.

		      kernel - the route was installed by the kernel during autoconfiguration.

		      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 protocol.

	      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.

   ip route delete - delete route
       ip route del has the same arguments as ip route add, but their semantics are a bit differ-

       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

       to SELECTOR (default)
	      only select routes from the given range of destinations.	SELECTOR 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 PREFIX.  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 pre-
	      fix. 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 desti-
	      nations.	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 PREFIX.

       src PREFIX
	      only list routes with preferred source addresses selected by PREFIX.

       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 subsection.

   ip route get - get a single route
       this command gets a single route to a destination and prints its contents 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 route.

       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  inter-
       face and searches for a path to forward the packet.

   ip route save - save routing table information to stdout
       this  command  behaves  like ip route show except that the output is raw data suitable for
       passing to ip route restore.

   ip route restore - restore routing table information from stdin
       this command expects to read a data stream as  returned	from  ip  route  save.	 It  will
       attempt	to  restore  the  routing  table information exactly as it was at the time of the
       save, so any translation of information in the stream (such as  device  indexes)  must  be
       done  first.   Any  existing  routes are left unchanged.  Any routes specified in the data
       stream that already exist in the table will be ignored.

ip rule - routing policy database management
       Rules in the routing policy database control the route selection algorithm.

       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 destina-
       tion 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 'routing  policy  database'  (or  RPDB),  which
       selects routes by executing some set of rules.

       Each  policy  routing  rule  consists  of a selector and an action predicate.  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 selec-
       tor 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 program continues on the next rule.

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

       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 table containing high priority control routes
	      for local and broadcast addresses.

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

       2.     Priority: 32766, Selector: match anything, Action: lookup routing  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 routing 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 trans-
       late/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  ref-
	       erenced 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 pro-
	       hibited' 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 subsec-

       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 loopback, the  rule  only
	      matches  packets	originating from this host.  This means that you may create sepa-
	      rate routing tables for forwarded and local packets and, hence,  completely  segre-
	      gate them.

       oif NAME
	      select  the outgoing device to match.  The outgoing interface is only available for
	      packets originating from local sockets that are bound to a device.

       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 immedi-
	      ately.  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 inter-
       face.  Note that it is impossible to join protocol multicast groups statically.	This com-
       mand only manages link layer addresses.

       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  routing  engine,  it  is
       impossible  to  change mroute objects administratively, so we may only display them.  This
       limitation will be removed in the future.

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

       iif NAME
	      the interface on which multicast packets are received.

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

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 IPv4.

   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 gre.
	      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 packets.  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 end-
	      point 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 direc-
	      tions.  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 packets.  The icsum flag requires that all
	      input packets have the correct checksum.	The csum flag is equivalent to the combi-
	      nation icsum ocsum.

       seq, iseq, oseq
	      ( only GRE tunnels ) serialize packets.  The oseq flag enables sequencing of outgo-
	      ing 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 header.

       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 gen-
       erated with the rtmon utility.  This utility has a command line syntax similar to ip moni-
       tor.  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, destina-
	      tion 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.  Valid algorithms are: 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, code  also
	      number and key as dotted-quad or 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 beet.

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

       UPSPEC is  specified by sport and dport (for UDP/TCP), type and code (for ICMP; as number)
	      or key (for GRE; as dotted-quad or 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 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:

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

iproute2				 17 January 2002				    IP(8)

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