NAME

       ip-tunnel - tunnel configuration

SYNOPSIS

       ip [ OPTIONS ] tunnel  { COMMAND | help }

       ip tunnel { add | change | del | show | prl } [ NAME ]
               [ mode MODE ] [ remote ADDR ] [ local ADDR ]
               [ [i|o]seq ] [ [i|o]key KEY ] [ [i|o]csum ] ]
               [ encaplimit ELIM ] [ ttl TTL ]
               [ tos TOS ] [ flowlabel FLOWLABEL ]
               [ prl-default ADDR ] [ prl-nodefault ADDR ] [ prl-delete ADDR ]
               [ [no]pmtudisc ] [ dev PHYS_DEV ]

       MODE :=  { ipip | gre | sit | isatap | ip6ip6 | ipip6 | ip6gre | 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 }

       TIME := NUMBER[s|ms]

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 and gre.
                     Modes for IPv6 encapsulation available: ip6ip6, ipip6, ip6gre, 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  set a fixed TTL 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.

              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 isn'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.

       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>