VoIP, VLAN, IP Helper, DHCP, and Cabling Errors Worksheet

A company has a VLAN for voice traffic and another for data traffic. The VoIP phones are configured to tag voice VLAN traffic. What is the primary benefit of separating voice and data VLANs?

• Reduces IP address usage

• Minimizes broadcast traffic and improves call quality

• Eliminates the need for DHCP

• Automatically encrypts VoIP calls

A VoIP phone fails to obtain an IP address. The phone is connected to a switch port configured for VLAN 20 (voice), but the DHCP server is on VLAN 10 (data). Which configuration will fix the issue?

• Enable IP helper on the router for VLAN 20

• Change phone to VLAN 10

• Assign a static IP to the phone

• Enable STP

Which of the following is the primary function of an IP helper address on a router?

• Forward DNS requests to a remote server

• Forward broadcast requests like DHCP to a specific server

• Block unauthorized DHCP requests

• Encrypt traffic between VLANs

A technician notices that a newly terminated Ethernet cable is not connecting devices. What is the most likely cause?

• The cable wires are not properly terminated.

• The network switch is powered off.

• The device drivers are outdated.

• The Ethernet cable is too short.

Which tool is BEST to test for wiring faults like miswires, shorts, or open pairs?

• Cable tester

• Multimeter

• Loopback plug

• Spectrum analyzer

Which type of cabling error can cause intermittent connectivity and poor network performance?

• Crosstalk due to improper twisting of wire pairs

• Using patch cables instead of straight-through cables

• VLAN misconfiguration

• NAT misconfiguration

Which NAT type allows many internal devices to share one public IP address using different port numbers?

• Static NAT

• Dynamic NAT

• PAT (Port Address Translation)

• NAT loopback

A company uses NAT on the edge router. After configuring PAT, some internal services are unreachable from the internet. What is the most likely cause?

• VLAN mismatch

• Missing port forwarding for services

• DHCP misconfiguration

• DNS resolution errors

Which DNS record is used to specify the mail server responsible for receiving email for a domain?

• A record

• MX record

• CNAME record

• PTR record

Which record allows multiple hostnames to map to the same canonical domain name?

• A record

• MX record

• CNAME record

• TXT record