Cisco Cisco IOS Software Release 12.2(27)SBC
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L2TP Security
The L2TP security feature allows the security features of IP Security (IPSec) to protect the Layer 2
Tunnel Protocol (L2TP) virtual private dialup network (VPDN) tunnel and the PPP sessions within the
tunnel. Without L2TP security, only a one-time, optional mutual authentication is performed during
tunnel setup, with no authentication of subsequent data packets or control messages.
Tunnel Protocol (L2TP) virtual private dialup network (VPDN) tunnel and the PPP sessions within the
tunnel. Without L2TP security, only a one-time, optional mutual authentication is performed during
tunnel setup, with no authentication of subsequent data packets or control messages.
The enhanced protection provided by L2TP security increases the integrity and confidentiality of
tunneled PPP sessions. The security features of IPSec and Internet Key Exchange (IKE) include
confidentiality, integrity checking, replay protection, authentication, and key management. Traditional
routing protocols such as Routing Information Protocol (RIP), Open Shortest Path First (OSPF), and
Interior Gateway Routing Protocol (IGRP) will run transparently because a real PPP interface is
associated with the secure tunnel.
tunneled PPP sessions. The security features of IPSec and Internet Key Exchange (IKE) include
confidentiality, integrity checking, replay protection, authentication, and key management. Traditional
routing protocols such as Routing Information Protocol (RIP), Open Shortest Path First (OSPF), and
Interior Gateway Routing Protocol (IGRP) will run transparently because a real PPP interface is
associated with the secure tunnel.
Configuration Information
Configuration information is included in the “Configuring Additional VPDN Features” module in the
, Release 12.4T, at the following URL:
Command Reference
This section documents modified commands.
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