|  | # | 
|  | # Layer Two Tunneling Protocol (L2TP) | 
|  | # | 
|  |  | 
|  | menuconfig L2TP | 
|  | tristate "Layer Two Tunneling Protocol (L2TP)" | 
|  | depends on (IPV6 || IPV6=n) | 
|  | depends on INET | 
|  | ---help--- | 
|  | Layer Two Tunneling Protocol | 
|  |  | 
|  | From RFC 2661 <http://www.ietf.org/rfc/rfc2661.txt>. | 
|  |  | 
|  | L2TP facilitates the tunneling of packets across an | 
|  | intervening network in a way that is as transparent as | 
|  | possible to both end-users and applications. | 
|  |  | 
|  | L2TP is often used to tunnel PPP traffic over IP | 
|  | tunnels. One IP tunnel may carry thousands of individual PPP | 
|  | connections. L2TP is also used as a VPN protocol, popular | 
|  | with home workers to connect to their offices. | 
|  |  | 
|  | L2TPv3 allows other protocols as well as PPP to be carried | 
|  | over L2TP tunnels. L2TPv3 is defined in RFC 3931 | 
|  | <http://www.ietf.org/rfc/rfc3931.txt>. | 
|  |  | 
|  | The kernel component handles only L2TP data packets: a | 
|  | userland daemon handles L2TP the control protocol (tunnel | 
|  | and session setup). One such daemon is OpenL2TP | 
|  | (http://openl2tp.org/). | 
|  |  | 
|  | If you don't need L2TP, say N. To compile all L2TP code as | 
|  | modules, choose M here. | 
|  |  | 
|  | config L2TP_DEBUGFS | 
|  | tristate "L2TP debugfs support" | 
|  | depends on L2TP && DEBUG_FS | 
|  | help | 
|  | Support for l2tp directory in debugfs filesystem. This may be | 
|  | used to dump internal state of the l2tp drivers for problem | 
|  | analysis. | 
|  |  | 
|  | If unsure, say 'Y'. | 
|  |  | 
|  | To compile this driver as a module, choose M here. The module | 
|  | will be called l2tp_debugfs. | 
|  |  | 
|  | config L2TP_V3 | 
|  | bool "L2TPv3 support" | 
|  | depends on L2TP | 
|  | help | 
|  | Layer Two Tunneling Protocol Version 3 | 
|  |  | 
|  | From RFC 3931 <http://www.ietf.org/rfc/rfc3931.txt>. | 
|  |  | 
|  | The Layer Two Tunneling Protocol (L2TP) provides a dynamic | 
|  | mechanism for tunneling Layer 2 (L2) "circuits" across a | 
|  | packet-oriented data network (e.g., over IP).  L2TP, as | 
|  | originally defined in RFC 2661, is a standard method for | 
|  | tunneling Point-to-Point Protocol (PPP) [RFC1661] sessions. | 
|  | L2TP has since been adopted for tunneling a number of other | 
|  | L2 protocols, including ATM, Frame Relay, HDLC and even raw | 
|  | ethernet frames. | 
|  |  | 
|  | If you are connecting to L2TPv3 equipment, or you want to | 
|  | tunnel raw ethernet frames using L2TP, say Y here. If | 
|  | unsure, say N. | 
|  |  | 
|  | config L2TP_IP | 
|  | tristate "L2TP IP encapsulation for L2TPv3" | 
|  | depends on L2TP_V3 | 
|  | help | 
|  | Support for L2TP-over-IP socket family. | 
|  |  | 
|  | The L2TPv3 protocol defines two possible encapsulations for | 
|  | L2TP frames, namely UDP and plain IP (without UDP). This | 
|  | driver provides a new L2TPIP socket family with which | 
|  | userspace L2TPv3 daemons may create L2TP/IP tunnel sockets | 
|  | when UDP encapsulation is not required. When L2TP is carried | 
|  | in IP packets, it used IP protocol number 115, so this port | 
|  | must be enabled in firewalls. | 
|  |  | 
|  | To compile this driver as a module, choose M here. The module | 
|  | will be called l2tp_ip. | 
|  |  | 
|  | config L2TP_ETH | 
|  | tristate "L2TP ethernet pseudowire support for L2TPv3" | 
|  | depends on L2TP_V3 | 
|  | help | 
|  | Support for carrying raw ethernet frames over L2TPv3. | 
|  |  | 
|  | From RFC 4719 <http://www.ietf.org/rfc/rfc4719.txt>. | 
|  |  | 
|  | The Layer 2 Tunneling Protocol, Version 3 (L2TPv3) can be | 
|  | used as a control protocol and for data encapsulation to set | 
|  | up Pseudowires for transporting layer 2 Packet Data Units | 
|  | across an IP network [RFC3931]. | 
|  |  | 
|  | This driver provides an ethernet virtual interface for each | 
|  | L2TP ethernet pseudowire instance. Standard Linux tools may | 
|  | be used to assign an IP address to the local virtual | 
|  | interface, or add the interface to a bridge. | 
|  |  | 
|  | If you are using L2TPv3, you will almost certainly want to | 
|  | enable this option. | 
|  |  | 
|  | To compile this driver as a module, choose M here. The module | 
|  | will be called l2tp_eth. |