ICND1 WAN Technologies & Network Security 2 — Questions and Answers
Question 1: Which WAN technology uses a series of virtual circuits identified by DLCIs to connect remote sites?
- ATM
- Frame Relay (Correct answer)
- ISDN
- MPLS
Correct answer: Frame Relay
Frame Relay uses Data Link Connection Identifiers (DLCIs) to identify virtual circuits between endpoints.
Question 2: A network administrator needs to block all Telnet access to routers from outside the corporate network. Which ACL entry accomplishes this?
- deny tcp any any eq 22
- deny tcp any any eq 23 (Correct answer)
- deny udp any any eq 23
- deny ip any any eq 23
Correct answer: deny tcp any any eq 23
Telnet operates on TCP port 23, so 'deny tcp any any eq 23' blocks all Telnet connections.
Question 3: What does the LMI (Local Management Interface) provide in a Frame Relay network?
- Encryption between endpoints
- Status signaling between the DTE and Frame Relay switch (Correct answer)
- IP address assignment to PVCs
- QoS marking for voice traffic
Correct answer: Status signaling between the DTE and Frame Relay switch
LMI provides keepalive and status signaling between the router (DTE) and the Frame Relay switch at the local loop.
Question 4: Which type of VPN allows remote users to securely access corporate resources over the internet using a client application?
- Site-to-site VPN
- GRE tunnel
- Remote-access VPN (Correct answer)
- MPLS VPN
Correct answer: Remote-access VPN
Remote-access VPNs use client software to allow individual users to connect securely to the corporate network.
Question 5: What is the primary purpose of NAT (Network Address Translation) in a WAN environment?
- To encrypt data in transit
- To allow private IP addresses to communicate over the public internet (Correct answer)
- To load-balance traffic across multiple WAN links
- To prioritize voice traffic over data
Correct answer: To allow private IP addresses to communicate over the public internet
NAT translates private RFC 1918 addresses to public IP addresses, enabling internet access from private networks.
Question 6: In PPP authentication, which protocol transmits the username and password in cleartext?
- CHAP
- EAP
- PAP (Correct answer)
- MS-CHAPv2
Correct answer: PAP
PAP (Password Authentication Protocol) sends credentials in cleartext, making it vulnerable to interception.
Question 7: Which Cisco IOS command displays the status of all configured Frame Relay PVCs on an interface?
- show frame-relay map
- show frame-relay pvc (Correct answer)
- show interface serial
- show frame-relay lmi
Correct answer: show frame-relay pvc
'show frame-relay pvc' displays statistics and status (ACTIVE, INACTIVE, DELETED) for each PVC.
ICND1 WAN Technologies & Network Security 2
Which WAN technology uses a series of virtual circuits identified by DLCIs to connect remote sites?