220-1101 Network Services — 15 Questions

Question 1

A technician is troubleshooting a network where users can access the internet but cannot reach a specific internal web server by its hostname. The server's IP is 10.0.0.5, and pinging 10.0.0.5 works. The technician checks the DNS server and finds an A record for the server's name pointing to 10.0.0.10. What is the most likely issue?

Accepted Answer

The DNS A record is incorrect. The DNS A record points to the wrong IP address (10.0.0.10 instead of 10.0.0.5), causing hostname resolution to fail for that server. This is a common DNS misconfiguration where the record does not match the actual server IP. Correcting the A record resolves the issue.

Answer

The DHCP server assigned the wrong IP to the server

Answer

The router's port forwarding is misconfigured

Answer

The server's firewall is blocking DNS queries

Question 2

A company deploys a load balancer to distribute traffic across three web servers. Users report that they occasionally see outdated content or are asked to log in repeatedly. Which network service configuration is most likely missing to maintain session persistence?

Accepted Answer

Session persistence (sticky sessions). Load balancers distribute traffic but without session persistence (sticky sessions), a user may be directed to different servers during a session, losing login state or cached data. Configuring the load balancer to use cookies or source IP affinity ensures the same server handles the session. DNS round-robin alone would cause similar issues.

Answer

DNS round-robin

Answer

DHCP reservation

Answer

Port forwarding

Question 3

A user configures their laptop to use a static IP address, subnet mask, and default gateway. They can ping other devices on the same subnet but cannot reach the internet. What network service is most likely missing from their configuration?

Accepted Answer

DNS server. With a static IP, the user must also configure a DNS server address to resolve domain names. Without DNS, they can communicate locally but cannot access internet resources by name. DHCP would auto-assign these settings, but static configuration requires manual entry.

Answer

DHCP server

Answer

NAT

Answer

Proxy server

Question 4

A company wants to allow employees to securely access the corporate network from home using their laptops. Which network service should be deployed to provide encrypted remote access?

Accepted Answer

VPN. A VPN (Virtual Private Network) creates an encrypted tunnel between a remote device and the corporate network, ensuring secure data transmission over the internet. DHCP and DNS do not provide encryption, and port forwarding alone does not secure remote access.

Answer

DHCP

Answer

DNS

Answer

Port forwarding

Question 5

A user reports that they can access internal resources using IP addresses but cannot access them using hostnames. Other users on the same network have no issues. What is the most likely cause?

Accepted Answer

The user's DNS settings are incorrect. The ability to use IP addresses but not hostnames points to a DNS resolution problem on the user's device. This could be due to a misconfigured DNS server address in the network settings or a local hosts file issue. Other users working normally suggests the problem is client-specific.

Answer

The DHCP server is out of addresses

Answer

The DNS server is down

Answer

The router's NAT is misconfigured

Question 6

A company's web server is accessible from the internet, but users report that the website loads slowly. The server's public IP is 203.0.113.10, and the internal IP is 192.168.1.10. The network administrator notices that the router's port forwarding rule is set to forward port 80 to 192.168.1.10:8080. What is the likely cause of the slow performance?

Accepted Answer

The port forwarding rule uses the wrong internal port. Port forwarding should map external port 80 to the server's internal port 80, not 8080 unless the server listens on 8080. If the server listens on port 80, the mismatch causes connection delays or errors as the router forwards to a closed port. Correcting the internal port resolves the issue.

Answer

The DNS server is misconfigured

Answer

The NAT table is full

Answer

The DHCP scope is exhausted

Question 7

A user reports that they cannot access any websites, but they can ping the IP address of a public DNS server (8.8.8.8). What is the most likely misconfigured network service?

Accepted Answer

DNS. The ability to ping an external IP but not access websites indicates that DNS resolution is failing. DNS translates domain names to IP addresses, and without it, web browsing fails even if the internet connection is working. The DHCP server or static DNS settings should be checked.

Answer

DHCP

Answer

NAT

Answer

Proxy

Question 8

A small office uses a single public IP address for internet access. The network administrator wants internal web servers to be reachable from the internet on port 80. Which network service should be configured on the router to allow this?

Accepted Answer

Port forwarding. Port forwarding allows external requests on a specific port to be redirected to an internal IP address and port. This is the standard method to make internal servers accessible from the internet when using NAT. Other options like DHCP or DNS do not handle port-based redirection.

Answer

DHCP

Answer

DNS

Answer

VPN

Question 9

A customer complains that their VoIP phone intermittently drops calls. A technician checks the network and finds high latency and jitter during peak hours. Which network service should be configured to prioritize VoIP traffic?

Accepted Answer

QoS. Quality of Service (QoS) is used to prioritize time-sensitive traffic like VoIP, reducing latency and jitter during congestion. DHCP assigns IPs, DNS resolves names, and VPN encrypts traffic but none prioritize packets. QoS markings (e.g., DSCP) ensure voice packets are handled first.

Answer

DHCP

Answer

DNS

Answer

VPN

Question 10

A network administrator wants to ensure that all devices on a subnet automatically receive IP addresses from a specific range, and that the lease time is set to 8 hours. Which configuration file or service should be modified?

Accepted Answer

DHCP scope. The DHCP server configuration controls IP address ranges (scopes) and lease times. By modifying the DHCP scope, the administrator can set the desired IP range and lease duration. DNS and NAT do not manage IP assignment, and QoS handles traffic prioritization.

Answer

DNS zone file

Answer

NAT rules

Answer

QoS policy

Question 11

A small office has a single internet connection and needs to allow multiple internal devices to share that connection. The router's public IP is assigned by the ISP. Which network service must be enabled on the router to allow internal devices to communicate with external servers?

Accepted Answer

NAT. NAT (Network Address Translation) allows multiple devices on a private network to share a single public IP address by translating their private IPs to the public IP. DHCP assigns internal IPs but does not enable internet sharing. DNS resolves names, and PAT is a form of NAT but not the broad service name.

Answer

DHCP

Answer

DNS

Answer

PAT

Question 12

A technician is configuring a new file server and wants to ensure that when users type \fileserver in File Explorer, it resolves to the correct IP address. The network uses a Windows domain with Active Directory. Which network service should the technician configure to allow hostname resolution for this server?

Accepted Answer

DNS. In a Windows domain, DNS is the primary method for resolving hostnames to IP addresses, especially for servers. The technician should add an A record for the file server in the DNS zone. DHCP assigns IPs but does not provide name resolution, and WINS is legacy for NetBIOS names.

Answer

DHCP

Answer

WINS

Answer

NAT

Question 13

A technician is troubleshooting an issue where a user's computer can access the internet but cannot connect to a network printer by its IP address. The printer is on the same subnet and is powered on. Pinging the printer's IP from the computer fails. Which network service is most likely causing the problem?

Accepted Answer

ARP. Since the printer is on the same subnet, no routing is needed; ARP is required to resolve the printer's IP to its MAC address. If ARP fails, the ping will fail. DNS is not used when connecting by IP, and DHCP is not involved since the computer already has an IP.

Answer

DNS

Answer

DHCP

Answer

NAT

Question 14

A network administrator is setting up a new branch office. The branch router must automatically obtain a public IP address from the ISP, and internal devices must receive private IP addresses from the router. Which combination of network services should be configured on the router?

Accepted Answer

DHCP client and DHCP server. The router needs DHCP client mode to obtain a public IP from the ISP, and DHCP server mode to assign private IPs to internal devices. DNS and NAT are also needed but the question asks for the services that provide IP addresses. NAT is required to translate private IPs to the public IP for internet access.

Answer

DHCP client and DNS server

Answer

DHCP server and NAT

Answer

DNS server and NAT

Question 15

A user reports that their computer cannot connect to the internet after being moved to a new office. The computer receives an IP address starting with 169.254.x.x. Which network service is failing to provide a valid IP configuration?

Accepted Answer

DHCP. An IP address in the 169.254.x.x range indicates that the computer has assigned itself an Automatic Private IP Address (APIPA) because it did not receive a response from a DHCP server. The DHCP service is failing or unreachable. DNS and NAT are not involved in IP assignment.

Answer

DNS

Answer

NAT

Answer

ARP