WAN Technologies & Network Security Flashcards

What is the default encapsulation type on a Cisco serial interface connected to another Cisco router?

Answer: HDLC

Cisco uses its own variation of HDLC (High-Level Data Link Control) as the default serial encapsulation.

An administrator applies an ACL outbound on an interface. Which traffic does this ACL evaluate?

Answer: Traffic leaving the router through that interface

An outbound ACL evaluates packets after the routing decision is made, as they exit the specified interface.

Which WAN technology uses 23 B-channels and 1 D-channel in its PRI (Primary Rate Interface) configuration in North America?

Answer: ISDN

ISDN PRI in North America provides 23 bearer (B) channels at 64 Kbps each plus one 64 Kbps delta (D) channel for signaling.

When configuring a site-to-site IPsec VPN, what is the purpose of IKE Phase 1?

Answer: To establish a secure management channel (ISAKMP SA) for IKE Phase 2 negotiation

IKE Phase 1 creates the ISAKMP Security Association, a secure authenticated channel used to negotiate the IPsec SA in Phase 2.

Which command correctly configures a named extended ACL on a Cisco router?

Answer: ip access-list extended WEBTRAFFIC

'ip access-list extended NAME' creates a named extended ACL in ACL configuration mode.

What does CIR (Committed Information Rate) represent in a Frame Relay network?

Answer: The minimum guaranteed bandwidth the provider will deliver on a PVC

CIR is the guaranteed minimum bandwidth that the service provider commits to delivering on a Frame Relay PVC.

A network administrator wants to prevent IP address spoofing on an interface by blocking packets with source addresses from RFC 1918 private ranges arriving on the outside interface. This is an example of which security technique?

Answer: Ingress filtering

Ingress filtering blocks packets arriving from the internet with private or internal source IP addresses, preventing spoofing attacks.