Published in August 1999 as proposed standard RFC 2661, L2TP has its origins primarily in two older tunneling protocols … See more

The entire L2TP packet, including payload and L2TP header, is sent within a User Datagram Protocol (UDP) datagram. A virtue of transmission over UDP (rather than TCP) is that it avoids the "TCP meltdown p… See more

An L2TP tunnel can extend across an entire PPP session or only across one segment of a two-segment session. This can be represented by four different tunneling models, namely:
• voluntary … See more

An L2TP packet consists of :
Field meanings:
Flags and version control flags indicating data/control packet and presence of length, sequence, and offset fields. Length (optional) T… See more

At the time of setup of L2TP connection, many control packets are exchanged between server and client to establish tunnel and session for each direction. One peer requests the other peer to assign a specific tun… See more

Because of the lack of confidentiality inherent in the L2TP protocol, it is often implemented along with IPsec. This is referred to as L2TP/IPsec, and is standardized in IETF RFC 3193. The process of … See more

Windows has had native support (configurable in control panel) for L2TP since Windows 2000. Windows Vista added 2 alternative tools, an MMC snap-in called "Windows Firewall with Advanced Security" (WFwAS) a… See more