
[L2TPv3](/l2tpv3) can be run over an [IPSec](/ipsec) tunnel providing the following advantages:

* Remote users can access a [VPN](/vpn) over a public IP network without a gateway or dedicated line
* No additional client software such as Cisco VPN client software is required

Note that L2TP over IPSec supports only IKEv1.  IKEv2 is not supported.



Links:

https://forum.networklessons.com/t/l2tpv3-layer-2-tunnel-protocol-version-3/2770/46?u=lagapides

https://networklessons.com/cisco/ccie-routing-switching-written/l2tpv3-layer-2-tunnel-protocol-version-3

https://www.cisco.com/c/en/us/td/docs/security/asa/asa97/configuration/vpn/asa-97-vpn-config/vpn-l2tp-ipsec.pdf

L2TPv3 over IPSec

IPv6 - NDP Neighbor Discovery Process

IPv6 - NDP preferred and valid lifetimes

IPv6 - Network and Interface Identifiers

IPv6 - RA suppression command

IPv6 - SLAAC

IPv6 - Site Local addresses

IPv6 - Solicited Node Multicast Address

IPv6 - Unique Local addresses

IPv6 - Valid and Preferred Addresses

IPv6 - destination guard

IPv6 - ipv6 nd prefix command

IPv6 - loopback address

IPv6 - prefix length

IPv6 - understanding how to enable IPv6 functionality and routing on an IOS device

IPv6 EIGRP static neighbors

IPv6 EUI-64 host address configuration method

IPv6 Neighbor Discovery Protocol Extensions

IPv6 RA Guard

IPv6 computing a global unicast address

IPv6 first hop security features on CML

IPv6 global unicast address

IPv6 link-local address

IPv6 minimum and maximum prefix lengths

IPv6 mobility features

IPv6 simplicity and complexity of various prefix values

IPv6 stateless DHCP active clients equals zero

IPv6 transition technologies

IPv6

IS-IS - DIS and Pseudonode

IS-IS - attached bit

IS-IS - route filtering

IS-IS - up-down bit

IS-IS multitopology support

IS-IS

ISDN

ISIS circuit-type command

ISP Peering

ISPs, tiers, transiting, and the Internet

Importance of self-study for CCIE or CCDE

Interface - configuring a range of interfaces

Interface - no carrier counter

Interface - show interfaces counters explained

Interface - unknown protocol drops

Interface speed and bandwidth

Interior Gateway Protocol (IGP)

Internet Exchange Point (IXP)

Internet Service Provider (ISP)

Intrusion prevention system (IPS)

Kron task scheduler

L2TPv3

LACP

LAG - Multi-Chassis LAG

LFA - Topology Independent LFA

LFA, remote LFA, and how they work together in OSPF

LISP - map request and reply process

LISP - what is it

LISP and overlapping address spaces

LISP debug traffic between two EIDs

LISP host mobility use cases

LISP where EID-to-RLOC mappings originate

LISP

Logging buffered command

Loop-Free Alternate (LFA) Fast Reroute (FRR)

Loop-Free Alternate (LFA) and remote LFA

Loops in layers 2 and 3

MAC Access List EtherType

MAC Access List

MAC address flapping

MAC address of all zeros

MAC address table - multiple entries of the same MAC address

MAC address table - show command on Nexus device

MAC address table populated using source address field

MAC address table static multicast entry

MAC address table

MAC address

MPLS - BGP customer prefixes do not appear in the LFIB

MPLS - Connecting IPv6 sites over an IPv4 backbone

MPLS - Disabling IPv4 address family in BGP for VPNv4

MPLS - Ethernet over MPLS (EoMPLS)

MPLS - L3VPN BGP EIGRP redistribution

MPLS - L3VPN BGP OSPF Redistribution

MPLS - LDP source interface

MPLS - Layer 2 VPNs

MPLS - Multi-VRF CE

MPLS - Segment Routing over MPLS

MPLS - Transport Profile

MPLS - Using the BGP Allow-AS in feature

MPLS - VPN label

MPLS - VPNv4 Labels are assigned per route

MPLS - Virtual Private Network (VPN)

MPLS - label distribution using MP-BGP

MPLS - label

MPLS - multiarea OSPF in the core

MPLS - network redundancy

MPLS - what is fate sharing

MPLS - what is seamless MPLS

MPLS 6PE uses two labels in the data plane

MPLS Bytes Label Switched in the LFIB