l2tp(4) - NetBSD Manual Pages

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L2TP(4)                 NetBSD Kernel Interfaces Manual                L2TP(4)


NAME

     l2tp -- layer two tunneling protocol version 3


SYNOPSIS

     pseudo-device l2tp


DESCRIPTION

     The l2tp interface implements version 3 of the Layer Two Tunneling Proto-
     col (L2TPv3).  It can tunnel layer 2 protocol traffic over IPv4 or IPv6,
     as specified in RFC3931.

     The L2TPv3 protocol is comprised of two types of messages: control mes-
     sages and data messages.  Control messages are used in the establishment,
     maintenace, and clearing of control connections and sessions.  The l2tp
     interface can send control messages and data messages; furthermore the
     management of control messages is entrusted to userland daemon.  Without
     a management daemon, the l2tp interface can send data messages using the
     ifconfig(8) tunnel and session subcommands, or the SIOCSIFPHYADDR and
     SIOCSL2TPSESSION ioctls.  Additionally, it can use cookies specified in
     RFC3931 by using the ifconfig(8) cookie subcommand, or the
     SIOCSL2TPCOOKIE ioctl.

   Packet format
     Layer 2 frames are prepended with a L2TPv3 header as described by RFC
     3931.  The resulting L2TPv3 packets will be encapsulated in an outer
     packet, which may be either an IPv4 or IPv6 packet, with IP protocol num-
     ber 115.


EXAMPLES

     Configuration example:

     wm0 = 192.168.0.1/24                        wm0 = 192.168.0.2/24

     +------------+                                    +------------+
     |  NetBSD_A  |                                    |  NetBSD_B  |
     |------------|                                    |------------|
     |   [l2tp0] - - - - - - - - (tunnel) - - - - - - - - [l2tp0]   |
     |          [wm0]------------- ... --------------[wm0]          |
     |            |                                    |            |
     +---[wm1]----+                                    +----[wm1]---+
           |                                                  |
           |                                                  |
     +------------+                                    +------------+
     |   Host_X   |                                    |   Host_Y   |
     +------------+                                    +------------+

   Configuration example without cookies
     On NetBSD_A:

     # ifconfig wm0 inet 192.168.0.1/24
     # ifconfig l2tp0 create
     # ifconfig l2tp0 tunnel 192.168.0.1 192.168.0.2
     # ifconfig l2tp0 session 1234 4321
     # ifconfig bridge0 create
     # brconfig bridge0 add wm1
     # brconfig bridge0 add l2tp0
     # ifconfig l2tp0 up
     # ifconfig wm1 up
     # ifconfig bridge0 up

     On NetBSD_B:

     # ifconfig wm0 inet 192.168.0.2/24
     # ifconfig l2tp0 create
     # ifconfig l2tp0 tunnel 192.168.0.2 192.168.0.1
     # ifconfig l2tp0 session 4321 1234
     # ifconfig bridge0 create
     # brconfig bridge0 add wm1
     # brconfig bridge0 add l2tp0
     # ifconfig l2tp0 up
     # ifconfig wm1 up
     # ifconfig bridge0 up

   Configuration example with cookies
     On NetBSD_A:

     # ifconfig wm0 inet 192.168.0.1/24
     # ifconfig l2tp0 create
     # ifconfig l2tp0 tunnel 192.168.0.1 192.168.0.2
     # ifconfig l2tp0 session 1234 4321
     # ifconfig l2tp0 cookie 4 12345 4 54321
     # ifconfig bridge0 create
     # brconfig bridge0 add wm1
     # brconfig bridge0 add l2tp0
     # ifconfig l2tp0 up
     # ifconfig wm1 up
     # ifconfig bridge0 up

     On NetBSD_B:

     # ifconfig wm0 inet 192.168.0.2/24
     # ifconfig l2tp0 create
     # ifconfig l2tp0 tunnel 192.168.0.2 192.168.0.1
     # ifconfig l2tp0 session 4321 1234
     # ifconfig l2tp0 cookie 4 54321 4 12345
     # ifconfig bridge0 create
     # brconfig bridge0 add wm1
     # brconfig bridge0 add l2tp0
     # ifconfig l2tp0 up
     # ifconfig wm1 up
     # ifconfig bridge0 up


SEE ALSO

     inet(4), inet6(4), ifconfig(8)

     J. Lau, Ed., M. Townsley, Ed., and I. Goyret, Ed., "Layer Two Tunneling
     Protocol - Version 3 (L2TPv3)", RFC 3931,
     ftp://ftp.ietf.org/rfc/rfc3931.txt, March 2005.


HISTORY

     The l2tp device first appeared in NetBSD 8.0.


BUGS

     Currently, the l2tp interface supports Ethernet frames over IPv4 or IPv6
     only.

NetBSD 10.1                     August 14, 2018                    NetBSD 10.1