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.

              encaplim 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)

AUTHOR

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