man > ip-route(8)

IP-ROUTE(8)                                     Linux                                    IP-ROUTE(8)

NAME
       ip-route - routing table management

SYNOPSIS
       ip [ ip-OPTIONS ] route  { COMMAND | help }


       ip route { show | flush } SELECTOR

       ip route save SELECTOR

       ip route restore

       ip route get ROUTE_GET_FLAGS ADDRESS [ from ADDRESS iif STRING  ] [ oif STRING ] [ mark MARK
               ] [ tos TOS ] [ vrf NAME ] [ ipproto PROTOCOL ] [ sport NUMBER ] [ dport NUMBER ]

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

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

       ROUTE := NODE_SPEC [ INFO_SPEC ]

       NODE_SPEC := [ TYPE ] PREFIX [ tos TOS ] [ table TABLE_ID ] [ proto RTPROTO ] [ scope SCOPE ]
               [ metric METRIC ] [ ttl-propagate { enabled | disabled } ]

       INFO_SPEC := { NH | nhid ID } OPTIONS FLAGS [ nexthop NH ] ...

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

       FAMILY := [ inet | inet6 | mpls | bridge | link ]

       OPTIONS := FLAGS [ mtu NUMBER ] [ advmss NUMBER ] [ as [ to ] ADDRESS ] rtt TIME ] [ rttvar
               TIME ] [ reordering NUMBER ] [ window NUMBER ] [ cwnd NUMBER ] [ ssthresh NUMBER ] [
               realms REALM ] [ rto_min TIME ] [ initcwnd NUMBER ] [ initrwnd NUMBER ] [ features
               FEATURES ] [ quickack BOOL ] [ congctl NAME ] [ pref PREF ] [ expires TIME ] [
               fastopen_no_cookie BOOL ]

       TYPE := [ unicast | local | broadcast | multicast | throw | unreachable | prohibit | black‐
               hole | nat ]

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

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

       NHFLAGS := [ onlink | pervasive ]

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

       FEATURES := [ ecn | ]

       PREF := [ low | medium | high ]

       ENCAP := [ ENCAP_MPLS | ENCAP_IP | ENCAP_BPF | ENCAP_SEG6 | ENCAP_SEG6LOCAL | ENCAP_IOAM6 ]

       ENCAP_MPLS := mpls [ LABEL ] [ ttl TTL ]

       ENCAP_IP := ip id TUNNEL_ID dst REMOTE_IP [ src SRC ] [ tos TOS ] [ ttl TTL ]

       ENCAP_BPF := bpf [ in PROG ] [ out PROG ] [ xmit PROG ] [ headroom SIZE ]

       ENCAP_SEG6 := seg6 mode [ encap | encap.red | inline | l2encap | l2encap.red ] segs SEGMENTS
               [ hmac KEYID ]

       ENCAP_SEG6LOCAL := seg6local action SEG6_ACTION [ SEG6_ACTION_PARAM ] [ count ]

       ENCAP_IOAM6 := ioam6 [ freq K/N ] mode [ inline | encap | auto ] [ tundst ADDRESS ] trace
               prealloc type IOAM6_TRACE_TYPE ns IOAM6_NAMESPACE size IOAM6_TRACE_SIZE

       ROUTE_GET_FLAGS :=  [ fibmatch  ]


DESCRIPTION
       ip route is used to manipulate entries in the kernel routing tables.

       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 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 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 via.
               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 in‐
               valid 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 2^32-1 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 use.


       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 uni‐
                     cast.  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 pre‐
                     fix  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
                     /etc/iproute2/rt_dsfield.


              metric NUMBER

              preference NUMBER
                     the  preference value of the route.  NUMBER is an arbitrary 32bit number, where
                     routes with lower values are preferred.


              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.


              vrf NAME
                     the  vrf  name to add this route to. Implicitly means the table associated with
                     the VRF.


              dev NAME
                     the output device name.


              via [ FAMILY ] ADDRESS
                     the address of the nexthop router, in the address family FAMILY.  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 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  compati‐
                     bility with previous releases.  Otherwise if a suffix of s, sec or secs is used
                     to specify seconds and ms, msec or msecs to specify milliseconds.



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


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


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


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


              initcwnd NUMBER (Linux 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 (Linux 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.


              features FEATURES (Linux3.18+only)
                     Enable or disable per-route features. Only available feature at  this  time  is
                     ecn  to  enable explicit congestion notification when initiating connections to
                     the given destination network.  When responding to a  connection  request  from
                     the given network, ecn will also be used even if the net.ipv4.tcp_ecn sysctl is
                     set to 0.


              quickack BOOL (Linux 3.11+ only)
                     Enable or disable quick ack for connections to this destination.


              fastopen_no_cookie BOOL (Linux 4.15+ only)
                     Enable TCP Fastopen without a cookie for connections to this destination.


              congctl NAME (Linux 3.20+ only)

              congctl lock NAME (Linux 3.20+ only)
                     Sets  a specific TCP congestion control algorithm only for a given destination.
                     If not specified, Linux keeps the current global default TCP congestion control
                     algorithm, or the one set from the application. If the  modifier  lock  is  not
                     used,  an  application may nevertheless overwrite the suggested congestion con‐
                     trol algorithm for that destination. If the modifier lock is used, then an  ap‐
                     plication  is  not  allowed to overwrite the specified congestion control algo‐
                     rithm for that destination, thus it will be enforced/guaranteed to use the pro‐
                     posed algorithm.


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


              reordering NUMBER (Linux 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 syn‐
                     tax similar to the top level argument lists:

                             via [ FAMILY ] ADDRESS - is the nexthop router.


                             dev NAME - is the output device.


                             weight  NUMBER  - is a weight for this element of a multipath route re‐
                             flecting its relative bandwidth or quality.

                     The internal buffer used in iproute2 limits the maximum number of nexthops that
                     may be specified in one go. If only ADDRESS is given, the current  buffer  size
                     allows for 144 IPv6 nexthops and 253 IPv4 ones. For IPv4, this effectively lim‐
                     its  the number of nexthops possible per route. With IPv6, further nexthops may
                     be appended to the same route via ip route append command.


              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 redirect.


                             kernel - the route was installed by the  kernel  during  autoconfigura‐
                             tion.


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


                             static - the route was installed by the administrator to  override  dy‐
                             namic routing. Routing daemon will respect them and, probably, even ad‐
                             vertise 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.


              pref PREF
                     the IPv6 route preference.  PREF is a string specifying the route preference as
                     defined in RFC4191 for Router Discovery messages. Namely:

                             low - the route has a lowest priority


                             medium - the route has a default priority


                             high - the route has a highest priority



              nhid ID
                     use nexthop object with given id as nexthop specification.


              encap ENCAPTYPE ENCAPHDR
                     attach tunnel encapsulation attributes to this route.

                     ENCAPTYPE is a string specifying the supported encapsulation type. Namely:

                             mpls - encapsulation type MPLS

                             ip - IP encapsulation (Geneve, GRE, VXLAN, ...)

                             bpf - Execution of BPF program

                             seg6 - encapsulation type IPv6 Segment Routing

                             seg6local - local SRv6 segment processing

                             ioam6 - encapsulation type IPv6 IOAM

                             xfrm - encapsulation type XFRM

                     ENCAPHDR is a set of encapsulation attributes specific to the ENCAPTYPE.

                             mpls
                               MPLSLABEL - mpls label stack with labels separated by /


                               ttl TTL - TTL to use for MPLS header or 0 to inherit from IP header


                             ip
                               id  TUNNEL_ID dst REMOTE_IP [ src SRC ] [ tos TOS ] [ ttl TTL ] [ key
                               ] [ csum ] [ seq ]


                             bpf
                               in PROG - BPF program to execute for incoming packets


                               out PROG - BPF program to execute for outgoing packets


                               xmit PROG - BPF program to execute for transmitted packets


                               headroom SIZE - Size of header BPF program will attach (xmit)


                             seg6
                               mode inline - Directly  insert  Segment  Routing  Header  after  IPv6
                               header


                               mode encap - Encapsulate packet in an outer IPv6 header with SRH


                               mode  encap.red - Encapsulate packet in an outer IPv6 header with SRH
                               applying the reduced segment list. When there is only one segment and
                               the HMAC is not present, the SRH is omitted.


                               mode l2encap - Encapsulate ingress L2  frame  within  an  outer  IPv6
                               header and SRH


                               mode  l2encap.red - Encapsulate ingress L2 frame within an outer IPv6
                               header and SRH applying the reduced segment list. When there is  only
                               one segment and the HMAC is not present, the SRH is omitted.


                               SEGMENTS - List of comma-separated IPv6 addresses


                               KEYID - Numerical value in decimal representation. See ip-sr(8).


                             seg6local
                               SEG6_ACTION [ SEG6_ACTION_PARAM ] [ count ] - Operation to perform on
                               matching  packets.  The  optional  count attribute is used to collect
                               statistics on the processing of actions.  Three counters  are  imple‐
                               mented: 1) packets correctly processed; 2) bytes correctly processed;
                               3)  packets  that  cause  a processing error (i.e., missing SID List,
                               wrong SID List, etc). To retrieve the counters related to  an  action
                               use  the -s flag in the show command.  The following actions are cur‐
                               rently supported (Linux 4.14+ only).

                                 End [ flavors FLAVORS ] - Regular SRv6 processing  as  intermediate
                                 segment endpoint.  This action only accepts packets with a non-zero
                                 Segments  Left value. Other matching packets are dropped. The pres‐
                                 ence of flavors can change the regular processing of an End  behav‐
                                 ior  according  to the user-provided Flavor operations and informa‐
                                 tion carried in the packet.  See Flavors parameters section.

                                 End.X nh6 NEXTHOP - Regular SRv6 processing as intermediate segment
                                 endpoint.  Additionally, forward processed packets to  given  next-
                                 hop.   This  action  only  accepts packets with a non-zero Segments
                                 Left value. Other matching packets are dropped.

                                 End.DX6 nh6 NEXTHOP - Decapsulate inner IPv6 packet and forward  it
                                 to  the  specified next-hop. If the argument is set to ::, then the
                                 next-hop is selected according to the local selection  rules.  This
                                 action  only accepts packets with either a zero Segments Left value
                                 or no SRH at all, and an inner IPv6 packet. Other matching  packets
                                 are dropped.

                                 End.DT6  {  table | vrftable } TABLEID - Decapsulate the inner IPv6
                                 packet and forward it according  to  the  specified  lookup  table.
                                 TABLEID   is   either   a   number   or  a  string  from  the  file
                                 /etc/iproute2/rt_tables.  If vrftable is used, the argument must be
                                 a VRF device associated with the table id. Moreover, the VRF  table
                                 associated with the table id must be configured with the VRF strict
                                 mode  turned  on  (net.vrf.strict_mode=1). This action only accepts
                                 packets with either a zero Segments Left value or no  SRH  at  all,
                                 and an inner IPv6 packet. Other matching packets are dropped.

                                 End.DT4  vrftable  TABLEID  - Decapsulate the inner IPv4 packet and
                                 forward it according to the specified lookup table.  TABLEID is ei‐
                                 ther a number or a string from  the  file  /etc/iproute2/rt_tables.
                                 The  argument  must  be  a VRF device associated with the table id.
                                 Moreover, the VRF table associated with the table id must  be  con‐
                                 figured with the VRF strict mode turned on (net.vrf.strict_mode=1).
                                 This  action  only accepts packets with either a zero Segments Left
                                 value or no SRH at all, and an inner IPv4  packet.  Other  matching
                                 packets are dropped.

                                 End.DT46  vrftable  TABLEID  -  Decapsulate  the inner IPv4 or IPv6
                                 packet and forward it according  to  the  specified  lookup  table.
                                 TABLEID   is   either   a   number   or  a  string  from  the  file
                                 /etc/iproute2/rt_tables.  The argument must be a VRF device associ‐
                                 ated with the table id.  Moreover, the VRF  table  associated  with
                                 the  table id must be configured with the VRF strict mode turned on
                                 (net.vrf.strict_mode=1). This action only accepts packets with  ei‐
                                 ther a zero Segments Left value or no SRH at all, and an inner IPv4
                                 or IPv6 packet. Other matching packets are dropped.

                                 End.B6  srh segs SEGMENTS [ hmac KEYID ] - Insert the specified SRH
                                 immediately after the IPv6 header, update the  DA  with  the  first
                                 segment  of  the  newly  inserted  SRH,  then forward the resulting
                                 packet. The original SRH is not modified. This action only  accepts
                                 packets with a non-zero Segments Left value. Other matching packets
                                 are dropped.

                                 End.B6.Encaps  srh segs SEGMENTS [ hmac KEYID ] - Regular SRv6 pro‐
                                 cessing as intermediate segment endpoint.   Additionally,  encapsu‐
                                 late  the  matching  packet within an outer IPv6 header followed by
                                 the specified SRH. The destination address of the outer IPv6 header
                                 is set to the first segment of the new SRH. The source  address  is
                                 set as described in ip-sr(8).

                                 Flavors parameters

                                 The  flavors represent additional operations that can modify or ex‐
                                 tend a subset of the existing behaviors.

                                   flavors OPERATION[,OPERATION] [ATTRIBUTES]

                                     OPERATION := { psp | usp | usd | next-csid }

                                     ATTRIBUTES := { KEY VALUE } [ ATTRIBUTES ]

                                     KEY := { lblen | nflen }

                                   psp - Penultimate Segment Pop of the SRH (not  yet  supported  in
                                   kernel)

                                   usp  - Ultimate Segment Pop of the SRH (not yet supported in ker‐
                                   nel)

                                   usd - Ultimate Segment Decapsulation (not yet supported  in  ker‐
                                   nel)

                                   next-csid  -  The  NEXT-C-SID mechanism offers the possibility of
                                   encoding several SRv6 segments within a single 128  bit  SID  ad‐
                                   dress.  The  NEXT-C-SID flavor can be configured to support user-
                                   provided Locator-Block and Locator-Node Function lengths. If  Lo‐
                                   cator-Block and/or Locator-Node Function lengths are not provided
                                   by the user during configuration of an SRv6 End behavior instance
                                   with  NEXT-C-SID flavor, the default value is 32-bit for Locator-
                                   Block and 16-bit for Locator-Node Function.

                                   lblen VALUE - defines the  Locator-Block  length  for  NEXT-C-SID
                                   flavor.   The  Locator-Block  length  must  be greater than 0 and
                                   evenly divisible by 8. This attribute can be used only with NEXT-
                                   C-SID flavor.

                                   nflen VALUE - defines the Locator-Node Function length for  NEXT-
                                   C-SID  flavors.  The Locator-Node Function length must be greater
                                   than 0 and evenly divisible by 8. This attribute can be used only
                                   with NEXT-C-SID flavor.

                               ioam6
                                 freq K/N - Inject IOAM in K packets every  N  packets  (default  is
                                 1/1).

                                 mode  inline  -  Directly  insert  IOAM  after IPv6 header (default
                                 mode).


                                 mode encap - Encapsulate packet in an outer IPv6 header with IOAM.


                                 mode auto - Automatically use inline mode for local packets and en‐
                                 cap mode for in-transit packets.


                                 tundst ADDRESS - IPv6 address  of  the  tunnel  destination  (outer
                                 header), not used with inline mode.

                                 type  IOAM6_TRACE_TYPE  -  List of IOAM data required in the trace,
                                 represented by a bitfield (24 bits).


                                 ns IOAM6_NAMESPACE - Numerical value to  represent  an  IOAM  name‐
                                 space. See ip-ioam(8).


                                 size IOAM6_TRACE_SIZE - Size, in octets, of the pre-allocated trace
                                 data block.

                               xfrm
                                 if_id IF_ID  [ link_dev LINK_DEV ]



              expires TIME (Linux 4.4+ only)
                     the  route  will  be  deleted  after  the  expires  time.  Only support IPv6 at
                     present.


              ttl-propagate { enabled | disabled }
                     Control whether TTL should be propagated from any encap  into  the  un-encapsu‐
                     lated  packet,  overriding any global configuration. Only supported for MPLS at
                     present.


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

              Key values (to, tos, preference and table) select the route to delete. If optional at‐
              tributes  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.  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  en‐
                     tire  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 se‐
                     lect 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 table  main.
                     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.


              vrf NAME
                     show the routes for the table associated with the vrf name


              cloned

              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  equiva‐
                     lent 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 [ FAMILY ] 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

              realms FROMREALM/TOREALM
                     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 ac‐
              tion: 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 de‐
              scribed 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.


              fibmatch
                     Return full fib lookup matched route. Default is to return the resolved dst en‐
                     try


              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.


              mark MARK
                     the firewall mark (fwmark)


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


              ipproto PROTOCOL
                     ip protocol as seen by the route lookup


              sport NUMBER
                     source port as seen by the route lookup


              dport NUMBER
                     destination port as seen by the route lookup


              connected
                     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 interface 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.


NOTES
       Starting  with Linux kernel version 3.6, there is no routing cache for IPv4 anymore. Hence ip
       route show cached will never print any entries on systems with this or newer kernel versions.


EXAMPLES
       ip ro
           Show all route entries in the kernel.

       ip route add default via 192.168.1.1 dev eth0
           Adds a default route (for all addresses) via the local gateway 192.168.1.1  that  can  be
           reached on device eth0.

       ip route add 10.1.1.0/30 encap mpls 200/300 via 10.1.1.1 dev eth0
           Adds an ipv4 route with mpls encapsulation attributes attached to it.

       ip  -6  route  add 2001:db8:1::/64 encap seg6 mode encap segs 2001:db8:42::1,2001:db8:ffff::2
       dev eth0
           Adds an IPv6 route with SRv6 encapsulation and two segments attached.

       ip -6 route add 2001:db8:1::/64 encap seg6local action End.DT46 vrftable 100 dev vrf100
           Adds an IPv6 route with SRv6 decapsulation and forward with lookup in VRF table.

       ip -6 route add 2001:db8:1::/64 encap seg6local action End flavors next-csid dev eth0
           Adds an IPv6 route with SRv6 End behavior with next-csid flavor enabled.

       ip -6 route add 2001:db8:1::/64 encap seg6local action End flavors next-csid lblen  48  nflen
       16 dev eth0
           Adds an IPv6 route with SRv6 End behavior with next-csid flavor enabled and user-provided
           Locator-Block and Locator-Node Function lengths.

       ip  -6  route add 2001:db8:1::/64 encap ioam6 freq 2/5 mode encap tundst 2001:db8:42::1 trace
       prealloc type 0x800000 ns 1 size 12 dev eth0
           Adds an IPv6 route with an IOAM Pre-allocated Trace encapsulation (ip6ip6) that only  in‐
           cludes the hop limit and the node id, configured for the IOAM namespace 1 and a pre-allo‐
           cated data block of 12 octets (will be injected in 2 packets every 5 packets).

       ip route add 10.1.1.0/30 nhid 10
           Adds an ipv4 route using nexthop object with id 10.

SEE ALSO
       ip(8)


AUTHOR
       Original Manpage by Michail Litvak <mci AT owl.com>

iproute2                                     13 Dec 2012                                 IP-ROUTE(8)
ip-route(8)
NAME SYNOPSIS
ip route restore
DESCRIPTION
Route types:
NOTES EXAMPLES SEE ALSO AUTHOR

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