# man > ip-tunnel(8)

[_IP-TUNNEL_(8)](https://www.chedong.com/phpMan.php/man/IP-TUNNEL/8/markdown)                                    Linux                                   [_IP-TUNNEL_(8)](https://www.chedong.com/phpMan.php/man/IP-TUNNEL/8/markdown)

## NAME
       ip-tunnel - tunnel configuration

## SYNOPSIS
### ip tunnel help

       **ip **[ _OPTIONS_ ] **tunnel **{ **add **| **change **| **del **| **show **| **prl **| **6rd **} [ _NAME_ ]
               [ **mode _**MODE_ ] [ **remote _**ADDR_ ] [ **local _**ADDR_ ]
               [ [**i**|**o**]**seq **] [ [**i**|**o**]**key _**KEY_ ] [ [**i**|**o**]**csum **] ]
               [ **encaplimit _**ELIM_ ] [ **ttl**|**hoplimit _**TTL_ ]
               [ **tos _**TOS_ ] [ **flowlabel _**FLOWLABEL_ ]
               [ **prl-default _**ADDR_ ] [ **prl-nodefault _**ADDR_ ] [ **prl-delete _**ADDR_ ]
               [ **6rd-prefix _**ADDR_ ] [ **6rd-relay_prefix _**ADDR_ ] [ **6rd-reset **]
               [ [**no**]**pmtudisc **] [ [**no**]**ignore-df **] [ [**no**]**allow-localremote **]
               [ **dev _**PHYS_DEV_ ]

       _MODE_ :=  { **ipip **| **gre **| **sit **| **isatap **| **vti **| **ip6ip6 **| **ipip6 **| **ip6gre **| **vti6 **| **any **}

       _ADDR_ := { _IP_ADDRESS_ | **any **}

       _TOS_ := { _STRING_ | _00_.._ff_ | **inherit **| **inherit/_**STRING_ | **inherit/_**00_**.._**ff_ }

       _ELIM_ := { **none **| _0_.._255_ }

       _TTL_ := { _1_.._255_ | **inherit **}

       _KEY_ := { _DOTTED_QUAD_ | _NUMBER_ }


## DESCRIPTION
       **tunnel **objects are tunnels, encapsulating packets in IP packets and then sending them over
       the IP infrastructure.  The encapsulating (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 fam‐
                     ily.
                     Modes for IPv4 encapsulation available: **ipip**, **sit**, **isatap**, **vti**, and **gre**.
                     Modes for IPv6 encapsulation available: **ip6ip6**, **ipip6**, **ip6gre**, **vti6**, 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 an‐
                     other interface of this host.


              **ttl _**N_

              **hoplimit _**N_
                     set a fixed TTL (IPv4) or hoplimit (IPv6) _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 the type of service (IPv4) or traffic class (IPv6) field on tunneled  pack‐
                     ets, which can be specified as either a two-digit hex value (e.g. c0) or a pre‐
                     defined  string  (e.g.  internet).   The  value  **inherit **causes the field to be
                     copied from the original IP header. The values **inherit/_**STRING_ or **inherit/_**00_**.._**ff_
                     will set the field to _STRING_ or _00_.._ff_ when tunneling non-IP packets.  The  de‐
                     fault value is 00.


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


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


              **ignore-df**
                     enable  IPv4 DF suppression on this tunnel.  Normally datagrams that exceed the
                     MTU will be fragmented; the presence of the DF flag  inhibits  this,  resulting
                     instead in an ICMP Unreachable (Fragmentation Required) message.  Enabling this
                     attribute causes the DF flag to be ignored.


              **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  **oc‐**
                     **sum  **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 combination **icsum ocsum**.


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


              **encaplimit _**ELIM_
                     ( **only IPv6 tunnels **) set a fixed encapsulation limit. Default is 4.


              **flowlabel _**FLOWLABEL_
                     ( **only IPv6 tunnels **) set a fixed flowlabel.


              **allow-localremote**
                     ( **only IPv6 tunnels **) allow remote endpoint on the local host.


### 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.


## SEE ALSO
       [**ip**(8)](https://www.chedong.com/phpMan.php/man/ip/8/markdown)


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

iproute2                                     20 Dec 2011                                [_IP-TUNNEL_(8)](https://www.chedong.com/phpMan.php/man/IP-TUNNEL/8/markdown)