.TH IP\-TUNNEL 8 "20 Dec 2011" "iproute2" "Linux"

.SH "NAME"

ip-tunnel - tunnel configuration

.SH "SYNOPSIS"

.sp

.ad l

.in +8

.ti -8

.B ip tunnel help

.sp

.ti -8

.BR "ip "

.RI "[ " OPTIONS " ]"

.BR "tunnel" " { " add " | " change " | " del " | " show " | " prl " | " 6rd " }"

.RI "[ " NAME " ]"

.br

.RB "[ " mode

.IR MODE " ] [ "

.B remote

.IR ADDR " ] [ "

.B  local

.IR ADDR " ]"

.br

.RB "[ [" i "|" o "]" seq " ] [ [" i "|" o "]" key

.IR KEY " ] [ "

.RB "[" i "|" o "]" csum " ] ]"

.br

.RB "[ " encaplimit

.IR ELIM " ]"

.RB "[ " ttl "|" hoplimit

.IR TTL " ]"

.br

.RB "[ " tos

.IR TOS " ] [ "

.B flowlabel

.IR FLOWLABEL " ]"

.br

.RB "[ " prl-default

.IR ADDR " ] [ "

.B prl-nodefault

.IR ADDR " ] [ "

.B prl-delete

.IR ADDR " ]"

.br

.RB "[ " 6rd-prefix

.IR ADDR " ] ["

.B 6rd-relay_prefix

.IR ADDR " ] [

.BR 6rd-reset " ]"

.br

.RB "[ [" no "]" pmtudisc " ]"

.RB "[ [" no "]" ignore-df " ]"

.RB "[ [" no "]" allow-localremote " ]"

.br

.RB "[ " dev

.IR PHYS_DEV " ]"

.ti -8

.IR MODE " := "

.RB " { " ipip " | " gre " | " sit " | " isatap " | " vti " | " ip6ip6 " | " ipip6 " | " ip6gre " | " vti6 " | " any " }"

.ti -8

.IR ADDR " := { " IP_ADDRESS " |"

.BR any " }"

.ti -8

.IR TOS " := { " STRING " | " 00 ".." ff " |"

.BR inherit " |"

.BI "inherit/" STRING

.RB "|"

.BI "inherit/" 00 ".." ff

.RB "}"

.ti -8

.IR ELIM " := {"

.BR none " | "

.IR 0 ".." 255 " }"

.ti -8

.ti -8

.IR TTL " := { " 1 ".." 255 " | "

.BR inherit " }"

.ti -8

.IR KEY " := { " DOTTED_QUAD " | " NUMBER " }"

.SH DESCRIPTION

.B 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

.B -f

option. The default is IPv4.

.TP

.B ip tunnel add

add a new tunnel

.TP

.B ip tunnel change

change an existing tunnel

.TP

.B ip tunnel delete

destroy a tunnel

.RS

.TP

.BI name " NAME " (default)

select the tunnel device name.

.TP

.BI mode " MODE"

set the tunnel mode. Available modes depend on the encapsulating address family.

.br

Modes for IPv4 encapsulation available:

.BR ipip ", " sit ", " isatap ", " vti ", and " gre "."

.br

Modes for IPv6 encapsulation available:

.BR ip6ip6 ", " ipip6 ", " ip6gre ", " vti6 ", and " any "."

.TP

.BI remote " ADDRESS"

set the remote endpoint of the tunnel.

.TP

.BI local " ADDRESS"

set the fixed local address for tunneled packets.

It must be an address on another interface of this host.

.TP

.BI ttl " N"

.TP

.BI hoplimit " N"

set a fixed TTL (IPv4) or hoplimit (IPv6)

.I N

on tunneled packets.

.I 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:

.BR "inherit" .

The default value for IPv6 tunnels is:

.BR "64" .

.TP

.BI tos " T"

.TP

.BI dsfield " T"

.TP

.BI 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

.B inherit

causes the field to be copied from the original IP header. The

values

.BI "inherit/" STRING

or

.BI "inherit/" 00 ".." ff

will set the field to

.I STRING

or

.IR 00 ".." ff

when tunneling non-IP packets. The default value is 00.

.TP

.BI dev " NAME"

bind the tunnel to the device

.I 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.

.TP

.B 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.

.TP

.B 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.

.TP

.BI key " K"

.TP

.BI ikey " K"

.TP

.BI okey " K"

.RB ( " only GRE tunnels " )

use keyed GRE with key

.IR K ". " K

is either a number or an IP address-like dotted quad.

The

.B key

parameter sets the key to use in both directions.

The

.BR ikey " and " okey

parameters set different keys for input and output.

.TP

.BR csum ", " icsum ", " ocsum

.RB ( " only GRE tunnels " )

generate/require checksums for tunneled packets.

The

.B ocsum

flag calculates checksums for outgoing packets.

The

.B icsum

flag requires that all input packets have the correct

checksum. The

.B csum

flag is equivalent to the combination

.BR "icsum ocsum" .

.TP

.BR seq ", " iseq ", " oseq

.RB ( " only GRE tunnels " )

serialize packets.

The

.B oseq

flag enables sequencing of outgoing packets.

The

.B iseq

flag requires that all input packets are serialized.

The

.B  seq

flag is equivalent to the combination

.BR "iseq oseq" .

.B It doesn't work. Don't use it.

.TP

.BI encaplim " ELIM"

.RB ( " only IPv6 tunnels " )

set a fixed encapsulation limit. Default is 4.

.TP

.BI flowlabel " FLOWLABEL"

.RB ( " only IPv6 tunnels " )

set a fixed flowlabel.

.TP

.BI allow-localremote

.RB ( " only IPv6 tunnels " )

allow remote endpoint on the local host.

.RE

.TP

.B ip tunnel prl

potential router list (ISATAP only)

.RS

.TP

.BI dev " NAME"

mandatory device name.

.TP

.BI prl-default " ADDR"

.TP

.BI prl-nodefault " ADDR"

.TP

.BI prl-delete " ADDR"

.RB "Add or delete " ADDR

as a potential router or default router.

.RE

.TP

.B ip tunnel show

list tunnels

This command has no arguments.

.SH SEE ALSO

.br

.BR ip (8)

.SH AUTHOR

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