Layer Two Tunneling Protocol (L2TP) Clients

Apr 16, 2018 · This article discusses how to configure a preshared key for use with Layer 2 Tunneling Protocol (L2TP). To use L2TP in Windows Server 2003, you must have a public key infrastructure (PKI) to issue computer certificates to the virtual private network (VPN) server and to clients so that the Internet Key Exchange (IKE) authentication process can occur. The Layer 2 Tunneling Protocol (L2TP) allows the transmission of frames between two nodes. A tunnel is not encrypted by default, it relies on the TCP/IP protocol chosen to determine the level of security. Mar 22, 2017 · A vulnerability in the Layer 2 Tunneling Protocol (L2TP) parsing function of Cisco IOS and Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause an affected device to reload. The vulnerability is due to insufficient validation of L2TP packets. An attacker could exploit this vulnerability by sending a crafted L2TP packet to an affected device. A successful exploit could Layer 2 Tunneling Protocol (L2TP) connections, which are also called virtual lines, provide cost-effective access for remote users by allowing a corporate network systems to manage the IP addresses assigned to its remote users.

L2TP was derived from PPTP features and features of an earlier Cisco protocol called L2F (Layer 2 Forwarding). L2TP supports TACACS+ and RADIUS authentication. PPTP does not. L2TP also supports more protocols than PPTP, including IPX, SNA, and others. Microsoft continues to support PPTP as a tunneling protocol for its Windows products, but L2TP

protocol Y protocol Z Layer 2 tunneling Payload is a data link layer (layer 2) frame Examples – PPTP – L2F – L2TP – piggybacks somebody else’s wire (eg, internet) 5 Layer 3 tunneling Payload is a network layer (layer 3) frame Examples – IP-over-IP – SSH port forwarding – IPSec What is Layer Two Forwarding (L2F)? - Definition from Layer Two Forwarding (L2F) is a Cisco tunneling protocol that uses virtual dial-up networks for secure data packet transport. L2F functionality is similar to the Point-to-Point Tunneling Protocol (PPTP), which was developed by the Microsoft-led PPTP Forum. L2F is part of the Layer 2 Tunneling Protocol (L2TP) standard (RFC 2661).

PPTP (point-to-point tunneling protocol) is a Microsoft-developed protocol that provides virtual dial-up services similar to L2TP. L2TP was derived from PPTP features and features of an earlier Cisco protocol called L2F (Layer 2 Forwarding). L2TP supports TACACS+ and RADIUS authentication. PPTP does not.

Layer 2 Tunneling Protocol - Wikipedia RFC 2341 Cisco Layer Two Forwarding (Protocol) "L2F" (a predecessor to L2TP) RFC 2637 Point-to-Point Tunneling Protocol (PPTP) (a predecessor to L2TP) RFC 2661 Layer Two Tunneling Protocol "L2TP" RFC 2809 Implementation of L2TP Compulsory Tunneling via RADIUS VPN client alternatives: Layer 2 Tunneling Protocol (L2TP L2TP L2TP is an IETF standard for tunneling Point-to-Point Protocol (PPP) across any intervening network. It forwards data transparently from an access concentrator (LAC) to a network server (LNS). The LAC may be an individual host or an ISP's network access server.