Tunneling
Why are tunnels important in Marine Corps networks?
They allow secure communications with far apart sites over transport paths
What is GRE designed to do?
Encapsulate traffic and carry it across an IP internetwork
IPsec works at which layer of the OSI model?
Network
What technology is commonly used to create a secure tunnel across a public or untrusted network?
VPN
What does DMVPN stand for?
Dynamic Multipoint Virtual Private Network
What does the "ip address" command configure on a tunnel interface?
The IP address of the overlay tunnel interface
What should be verified before building a GRE tunnel between two routers?
That the tunnel endpoints can reach each other through their physical interfaces (The Underlay Network)
What IPsec protocol is commonly used because it can encrypt traffic?
ESP
Why must data be protected when it crosses transport paths such as SatComm?
The traffic may travel across areas where it could be intercepted
At what Layer of the OSI model does NHRP operate?
Layer 2
In networking, what does a tunnel do to traffic?
It encapsulates one protocol inside another so the traffic can travel across a network
In a GRE configuration, what does the "tunnel source" command identify?
The physical interface or IP address where the tunnel starts
What security services does IPsec provide for IP communications?
Confidentiality, integrity, and data origin authentication
What type of VPN lets individual users connect securely to a central network from another location?
Remote access VPN
Which DMVPN phase improves spoke-to-spoke communication by using NHRP shortcuts and redirects?
Phase 3
What network does the tunnel interface IP address represent?
The overlay network
What does combining GRE with IPsec accomplish?
GRE supplies routing support while IPsec provides encryption and security
What is a Security Association?
It is a one-way agreement that defines the cryptographic settings used between peers
What type of VPN connects whole networks together across an untrusted network?
Site-to-site VPN
What three technologies are used to build DMVPN?
Multipoint GRE, NHRP, and IPsec
In a GRE tunnel, what does the tunnel destination usually point to?
The remote tunnel endpoint's physical IP address
Why is GRE useful for dynamic routing protocols such as BGP, EIGRP, and OSPF?
GRE can carry multicast and broadcast traffic
What does IPsec protect in a communication session?
Each IP packet using authentication and encryption
How many bytes is the full header added by a VPN?
24 bytes
What issue is solved by using a DMVPN deployment?
Scalability of secure tunnels between many distant locations.