# ip-tunnel

## 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 family.
                         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 another 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 packets, which can be
                         specified as either a two-digit hex value (e.g. c0)
                         or a predefined 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 default
                         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
                         directions.  The **ikey** and **okey** parameters set
                         different keys for input and output.
    
                  **csum** , **icsum** , **ocsum**
                         ( **only GRE tunnels**) generate/require checksums for
                         tunneled packets.  The **ocsum** flag calculates
                         checksums for outgoing 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
                         serialized.  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.
    


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