Courseiva

CCNA IP Addressing Questions

30 questions · IP Addressing topic · All types, answers revealed

Practice these questionsExam hubAll questions
1
MCQhard

A technician is troubleshooting a network where two computers cannot communicate. Computer A has an IP of 192.168.1.10 with subnet mask 255.255.255.0. Computer B has an IP of 192.168.2.20 with subnet mask 255.255.255.0. Both are connected to the same switch. The switch is not configured with VLANs. Why can't the computers communicate?

A.The switch is blocking the traffic due to MAC address filtering.
B.The computers are on different subnets and need a router to communicate.
C.The subnet mask on Computer B is incorrect.
D.The default gateway on both computers is not set.
AnswerB

Computers on different subnets cannot communicate directly; they require a router to forward packets between the subnets.

Why this answer

Even though both computers are on the same physical switch, they are on different logical subnets (192.168.1.0/24 and 192.168.2.0/24). Without a router to forward traffic between subnets, they cannot communicate directly.

Practice this question →
2
MCQmedium

A technician is setting up a new file server and needs to assign it a static IP address. The network uses a subnet of 192.168.1.0/24, and the router's LAN IP is 192.168.1.1. The technician wants to ensure the server is reachable from all devices on the local network. Which of the following IP addresses should the technician assign to the server?

A.192.168.1.0
B.192.168.1.255
C.192.168.1.50
D.192.168.2.1
AnswerC

Correct. 192.168.1.50 is within the usable range (1-254) and can be assigned as a static IP, provided it's not in the DHCP pool.

Why this answer

For a /24 subnet (255.255.255.0), usable addresses range from 192.168.1.1 to 192.168.1.254, but .1 is typically reserved for the router. The technician should choose an address outside the DHCP pool, such as 192.168.1.50, to avoid conflicts.

Practice this question →
3
MCQhard

A network engineer is designing a subnet scheme for a company with three departments: Sales (50 devices), HR (20 devices), and IT (10 devices). The company uses the 10.0.0.0/24 network. To minimize waste, the engineer decides to use variable-length subnet masking (VLSM). Which of the following subnet masks should be assigned to the Sales department?

A.255.255.255.128
B.255.255.255.192
C.255.255.255.224
D.255.255.255.240
AnswerB

Correct. A /26 provides 62 usable addresses, enough for 50 devices with minimal waste.

Why this answer

With VLSM, the largest subnet should be assigned first. Sales needs 50 usable addresses, so a /26 subnet (255.255.255.192) provides 62 usable addresses, which is sufficient and efficient. Smaller subnets would not accommodate 50 devices.

Practice this question →
4
MCQeasy

A user complains that they cannot access a website by its domain name, but they can access it by typing the IP address directly. The user's computer is configured to obtain DNS automatically. What is the most likely issue?

A.The user's computer has a static IP address that conflicts with another device.
B.The DNS server is not responding or is misconfigured.
C.The user's browser cache is corrupted.
D.The website's IP address has changed.
AnswerB

Since the user can reach the site by IP, the network connection is fine. The problem is with DNS, which translates domain names to IP addresses.

Why this answer

When a user can access a site by IP but not by domain name, it indicates a DNS resolution problem. The DNS server may be unreachable or not configured correctly.

Practice this question →
5
MCQmedium

A user reports that they can only access the internet intermittently. The technician runs ipconfig and sees an IPv4 address of 192.168.1.105 with a subnet mask of 255.255.255.0 and a default gateway of 192.168.1.1. The technician pings the gateway successfully, but pings to 8.8.8.8 fail. What is the most likely issue?

A.The user's computer has a duplicate IP address.
B.The DNS server is not resolving addresses.
C.The router's WAN connection is down or misconfigured.
D.The user's firewall is blocking ICMP traffic.
AnswerC

Since the local network works but external IPs are unreachable, the problem is likely with the router's connection to the ISP or its WAN settings.

Why this answer

Successful ping to the gateway indicates local network connectivity is fine. Failure to ping an external IP like 8.8.8.8 suggests the router is not forwarding traffic to the internet, possibly due to a WAN configuration issue or ISP problem.

Practice this question →
6
MCQmedium

A technician is troubleshooting a user's computer that cannot access a web server at 10.10.10.50. The user's IP is 10.10.20.15 with subnet mask 255.255.0.0. The technician can ping 10.10.10.50 from the user's computer. What should the technician check next?

A.The default gateway setting on the user's computer.
B.The web server's firewall settings.
C.The user's IP address for a conflict.
D.The subnet mask on the user's computer.
AnswerB

Since ICMP (ping) works but HTTP does not, a firewall on the server may be blocking the web traffic.

Why this answer

Since the user can ping the web server, network connectivity and IP addressing are correct. The issue is likely at the application layer, such as a firewall blocking HTTP/HTTPS or a misconfigured web server. This tests the OSI model and troubleshooting methodology.

Practice this question →
7
MCQmedium

A technician is configuring a small branch office network with 30 devices. The network uses a single router with DHCP enabled. To conserve IP addresses, the technician decides to use a subnet that provides exactly enough usable addresses for the devices, with minimal waste. Which subnet mask should the technician choose?

A.255.255.255.0
B.255.255.255.224
C.255.255.255.240
D.255.255.255.192
AnswerB

Correct. A /27 provides 30 usable addresses, exactly enough for 30 devices with minimal waste.

Why this answer

A /27 subnet (255.255.255.224) provides 30 usable addresses (32 total minus 2 reserved). This is the smallest subnet that accommodates 30 devices without wasting many addresses.

Practice this question →
8
MCQeasy

A user reports that they cannot access the internet, but they can ping other devices on the local network. The technician checks the IP configuration and sees: IP: 192.168.1.25, Subnet Mask: 255.255.255.0, Default Gateway: 192.168.2.1. What is the issue?

A.The subnet mask is incorrect.
B.The default gateway is on a different subnet.
C.The IP address is a broadcast address.
D.The DNS server is misconfigured.
AnswerB

The gateway 192.168.2.1 is on a different subnet than the device's IP 192.168.1.25, so the device cannot send packets to it.

Why this answer

The default gateway must be on the same subnet as the device's IP. Here, the IP is on 192.168.1.0/24, but the gateway is on 192.168.2.0/24, so traffic cannot be routed out. This tests the concept that the gateway must be reachable locally.

Practice this question →
9
MCQhard

A technician is troubleshooting a user's inability to reach a server at 172.16.50.100. The user's IP is 172.16.50.50 with subnet mask 255.255.255.0. The technician runs a traceroute and sees the first hop is the gateway (172.16.50.1), but the second hop times out. What does this indicate?

A.The user's IP address is in the wrong subnet.
B.The server is powered off.
C.There is a routing problem between the gateway and the server.
D.The user's default gateway is incorrect.
AnswerC

The traceroute shows the user can reach the gateway, but the next hop fails, indicating a routing issue in the path to the server.

Why this answer

The user can reach the local gateway, but the next hop (likely a router) is not responding. This suggests a routing issue beyond the local network, such as a misconfigured router or firewall blocking ICMP. This tests understanding of traceroute and routing path analysis.

Practice this question →
10
MCQmedium

A company has a network with the IP range 172.16.0.0/16. They need to create 8 separate subnets for different departments, each with at least 1000 usable hosts. What subnet mask should be used?

A.255.255.240.0
B.255.255.224.0
C.255.255.248.0
D.255.255.192.0
AnswerB

A /19 mask (255.255.224.0) provides 8 subnets (2^3) with 8190 usable hosts each, meeting both requirements.

Why this answer

To create 8 subnets from a /16 network, you need to borrow 3 bits (2^3=8 subnets). This gives a /19 subnet mask (255.255.224.0), which provides 8190 usable hosts per subnet (2^13-2), meeting the requirement of at least 1000 hosts.

Practice this question →
11
MCQmedium

A technician is setting up a small network for a home office. The router's WAN port receives a public IP of 203.0.113.5 from the ISP. The technician configures the LAN with a private IP range. Which of the following is a valid private IP address for the technician to assign to a workstation?

A.172.32.1.10
B.192.168.1.10
C.203.0.113.10
D.169.254.1.10
AnswerB

Correct. 192.168.1.10 is within the private 192.168.0.0/16 range and is commonly used for LANs.

Why this answer

Private IP addresses are defined in RFC 1918: 10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16. 192.168.1.10 falls within the 192.168.0.0/16 range, making it a valid private address for LAN use.

Practice this question →
12
MCQeasy

A customer reports that their laptop can connect to the internet at home but not at a coffee shop. The coffee shop uses a /24 subnet with a gateway of 192.168.1.1. The laptop's IP is 192.168.2.10. What is the most likely cause?

A.The DNS server address is incorrect.
B.The laptop's IP address is on a different subnet than the coffee shop's network.
C.The wireless card is faulty.
D.The subnet mask is set to 255.0.0.0.
AnswerB

The laptop's IP (192.168.2.10) is on the 192.168.2.0/24 subnet, while the coffee shop uses 192.168.1.0/24, preventing gateway communication.

Why this answer

The laptop's IP address is on a different subnet (192.168.2.0/24) than the coffee shop's network (192.168.1.0/24), so it cannot communicate with the gateway. This tests understanding of subnetting and how devices must be on the same subnet to reach the default gateway.

Practice this question →
13
MCQmedium

A customer reports that their new printer, configured with a static IP of 192.168.1.100, cannot be accessed from any computer on the network. The technician pings 192.168.1.100 from a workstation and gets no reply. The workstation's IP is 192.168.1.50 with a subnet mask of 255.255.255.0. What is the most likely cause?

A.The printer's IP address is on a different subnet than the workstation.
B.The printer's static IP address conflicts with another device on the network.
C.The workstation's subnet mask is set to 255.255.0.0.
D.The printer's default gateway is misconfigured.
AnswerB

Correct. An IP conflict can cause one or both devices to be unreachable. The technician should check for duplicate IPs.

Why this answer

Both devices are on the same /24 subnet, so the issue is not a subnet mismatch. The most common cause is an IP address conflict, where another device already uses 192.168.1.100, or the printer is not properly connected.

Practice this question →
14
MCQeasy

A user reports that their laptop cannot connect to the internet, but other devices on the same network work fine. The technician runs ipconfig and sees an IP address of 169.254.12.34 with a subnet mask of 255.255.0.0. What is the most likely cause of this issue?

A.The laptop has a static IP address configured incorrectly.
B.The DHCP server is not responding to the laptop's request.
C.The subnet mask is wrong; it should be 255.255.255.0.
D.The laptop's network adapter is faulty.
AnswerB

Correct. APIPA addresses are assigned when DHCP fails, so the DHCP server is likely unreachable or not responding.

Why this answer

An IP address in the 169.254.0.0/16 range is an Automatic Private IP Addressing (APIPA) address, assigned when a DHCP server is unreachable. This indicates the laptop failed to obtain a valid IP from the router's DHCP server.

Practice this question →
15
MCQeasy

A technician is setting up a small office with 15 devices and needs to assign private IP addresses. The router's LAN interface is 10.0.0.1/24. Which of the following is a valid IP address for a workstation on this network?

A.10.0.1.50
B.10.0.0.0
C.10.0.0.50
D.10.0.0.255
AnswerC

10.0.0.50 is within the valid host range of 10.0.0.1 to 10.0.0.254 for the /24 subnet.

Why this answer

The /24 subnet means the network is 10.0.0.0 with a range of 10.0.0.1 to 10.0.0.254. 10.0.0.50 falls within this range and is not reserved. This tests understanding of private IP ranges and subnet boundaries.

Practice this question →
16
MCQmedium

A small business uses a router with DHCP enabled, issuing addresses in the 192.168.1.0/24 range. A technician installs a new server with a static IP of 192.168.1.50, but users cannot connect to it. The technician pings 192.168.1.50 from the server itself successfully. What is the most likely cause?

A.The server's subnet mask is set to 255.255.255.0.
B.The server's default gateway is missing.
C.Another device on the network has the same IP address.
D.The server's network cable is faulty.
AnswerC

A static IP within the DHCP range can cause a conflict if the DHCP server assigns that address to another device, leading to intermittent connectivity.

Why this answer

If the DHCP server assigned 192.168.1.50 to another device, there is an IP address conflict. The server can ping itself because it uses its own IP, but other devices may have the same IP or the server's address is already in use. This tests understanding of IP conflicts and static vs.

DHCP assignments.

Practice this question →
17
MCQmedium

A technician is configuring a new printer on a network with the IP 172.16.0.50 and subnet mask 255.255.0.0. The router's LAN IP is 172.16.0.1. A workstation with IP 172.16.1.10 can ping the printer, but a workstation with IP 172.17.0.10 cannot. What is the most likely reason?

A.The printer's subnet mask is wrong.
B.The workstation with IP 172.17.0.10 is on a different network and needs a router to reach the printer.
C.The printer has a duplicate IP address.
D.The default gateway on the printer is missing.
AnswerB

172.17.0.10 is on the 172.17.0.0/16 network, which is separate from 172.16.0.0/16, so they require a router to communicate.

Why this answer

The subnet mask 255.255.0.0 means the network is 172.16.0.0/16, so 172.16.1.10 is on the same network, but 172.17.0.10 is on a different network (172.17.0.0/16). Without a router between them, they cannot communicate. This tests understanding of subnetting and how the subnet mask defines the network boundary.

Practice this question →
18
MCQeasy

A user reports that their laptop can connect to the internet when using a wired connection at home, but cannot connect to any network resources when using Wi-Fi at the office. The office uses DHCP with a scope of 192.168.10.0/24. The laptop's IP configuration shows an address of 169.254.15.22. What is the most likely cause of this issue?

A.The laptop's Wi-Fi adapter is disabled in Device Manager.
B.The office DHCP server is out of available IP addresses.
C.The laptop cannot reach the DHCP server on the office network.
D.The laptop's DNS settings are misconfigured.
AnswerC

APIPA is assigned when a DHCP server is not reachable, so the laptop cannot obtain a valid IP. This is the most direct explanation.

Why this answer

The address 169.254.x.x is an Automatic Private IP Addressing (APIPA) address, assigned when a DHCP server is unreachable. This indicates the laptop failed to obtain a valid IP from the office DHCP server, likely due to a connectivity or server issue.

Practice this question →
19
MCQhard

A network administrator is troubleshooting a connectivity issue between two servers. Server A has IP 192.168.10.25/25, and Server B has IP 192.168.10.200/25. Server A can ping its default gateway (192.168.10.1) but cannot ping Server B. What is the most likely cause?

A.Server A has a duplicate IP address.
B.The subnet mask is incorrect on one of the servers.
C.The servers are on different subnets and require a router to communicate.
D.The default gateway is misconfigured.
AnswerC

With a /25 mask, 192.168.10.25 is in the 0-126 range, and 192.168.10.200 is in the 128-254 range, placing them on different subnets.

Why this answer

A /25 subnet mask (255.255.255.128) divides the 192.168.10.0/24 network into two subnets: 192.168.10.0/25 (hosts 1-126) and 192.168.10.128/25 (hosts 129-254). Server A (25) is on the first subnet, Server B (200) on the second. They need a router to communicate.

This tests advanced subnetting.

Practice this question →
20
MCQhard

A network administrator is designing a new subnet scheme for a company with 4 departments: Sales (50 devices), HR (25 devices), IT (10 devices), and Management (5 devices). The company uses the 10.0.0.0/8 network. To minimize wasted IP addresses, which subnet mask should be used for the Sales department?

A.255.255.255.0
B.255.255.255.192
C.255.255.255.224
D.255.255.255.240
AnswerB

A /26 subnet provides 62 usable hosts, which is sufficient for 50 devices and minimizes waste.

Why this answer

To accommodate 50 devices, you need at least 52 usable addresses (50 + 2 for network and broadcast). A /26 subnet mask (255.255.255.192) provides 62 usable hosts, which is the smallest subnet that can support 50 devices without wasting many addresses.

Practice this question →
21
MCQmedium

A technician is setting up a new branch office and needs to assign IPs to 30 devices. The ISP provided a public IP block of 203.0.113.0/28. The technician decides to use private IPs internally and NAT. Which of the following is the most appropriate private IP range for this network?

A.203.0.113.1 to 203.0.113.14
B.10.0.0.0/8
C.192.168.1.0/24
D.172.16.0.0/12
AnswerC

192.168.1.0/24 is a private range that provides 254 usable addresses, ideal for a small office with 30 devices.

Why this answer

For a small network with 30 devices, a /24 subnet (e.g., 192.168.1.0/24) provides 254 usable addresses, which is sufficient. The /28 public block is for the WAN interface. This tests knowledge of private IP ranges (10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16) and subnet sizing.

Practice this question →
22
MCQeasy

A small office uses a single router with a built-in DHCP server. The office has 15 devices that need IP addresses. The router's default subnet mask is 255.255.255.0. How many usable IP addresses are available for devices on this subnet?

A.254
B.255
C.256
D.15
AnswerA

Correct. A /24 network has 256 total addresses minus 2 reserved addresses equals 254 usable addresses.

Why this answer

The subnet mask 255.255.255.0 corresponds to a /24 network, which provides 256 total addresses. After reserving the network address and broadcast address, 254 usable IP addresses remain, which is more than enough for 15 devices.

Practice this question →
23
MCQhard

A technician is configuring a new router for a branch office. The ISP provides a public IP of 203.0.113.10/30 for the WAN interface. How many usable IP addresses does the technician have for devices on the WAN link?

A.2
B.4
C.6
D.1
AnswerA

Correct. A /30 subnet has 2 usable addresses, typically used for the two ends of a point-to-point link.

Why this answer

A /30 subnet mask (255.255.255.252) provides 4 total addresses: one network, one broadcast, and two usable. This is commonly used for point-to-point WAN links to conserve public IPs.

Practice this question →
24
MCQmedium

A technician is troubleshooting a network where several users cannot access the internet, but they can communicate with each other. The network uses a router with IP 10.0.0.1 and a subnet mask of 255.255.255.0. All computers have IPs in the 10.0.0.0/24 range. What is the most likely cause?

A.The DNS server address is set to 10.0.0.1.
B.The subnet mask is incorrectly set to 255.255.0.0 on some computers.
C.The default gateway on the computers is not set to 10.0.0.1.
D.The router's DHCP server is disabled.
AnswerC

Without the correct default gateway, computers cannot send traffic outside their local subnet, which would prevent internet access.

Why this answer

If users can communicate locally but not access the internet, the issue is likely with the default gateway. The gateway must be correctly configured on each device and the router must have a route to the internet.

Practice this question →
25
MCQmedium

A technician is configuring a small office network with 15 computers and a single router. The router's WAN port is connected to a cable modem, and the LAN port is connected to a switch. All computers are connected to the switch. The technician assigns the router's LAN interface the IP 192.168.0.1/24. What should be the default gateway setting on each computer?

A.The IP address of the cable modem.
B.192.168.0.1
C.The IP address of the switch.
D.192.168.0.255
AnswerB

This is the router's LAN IP, which serves as the gateway for all computers on the local network to access other networks.

Why this answer

The default gateway is the IP address of the router's LAN interface, which is 192.168.0.1. This allows computers to send traffic outside their local subnet, such as to the internet.

Practice this question →
26
MCQeasy

A technician is setting up a new server that must always have the same IP address on a network using DHCP. The network administrator wants to avoid manually configuring the server's IP to prevent misconfiguration. Which method should be used to ensure the server receives the same IP from the DHCP server?

A.Set the server to use a static IP address outside the DHCP scope.
B.Configure a DHCP reservation on the router for the server's MAC address.
C.Set the server's IP address to 169.254.x.x.
D.Disable the server's network adapter and re-enable it.
AnswerB

A DHCP reservation assigns a fixed IP to a specific MAC address, ensuring the server always receives the same IP from DHCP.

Why this answer

A DHCP reservation ties a specific MAC address to a specific IP address in the DHCP server's configuration. This ensures the server always gets the same IP without manual static configuration.

Practice this question →
27
MCQeasy

A small business uses a router with a default IP of 192.168.1.1. The owner wants to set up a new printer with a static IP of 192.168.1.50. After configuring the printer, it cannot be accessed from any computer on the network. All computers are set to obtain IP addresses automatically. What is the most likely problem?

A.The printer's subnet mask is set to 255.0.0.0.
B.The printer's IP address is outside the router's DHCP range.
C.The printer's IP address conflicts with an address already assigned by DHCP.
D.The printer is not connected to the network via an Ethernet cable.
AnswerC

Since the router's DHCP range likely includes 192.168.1.50, another device may have been given that IP, causing a conflict and preventing the printer from being reached.

Why this answer

The printer's static IP falls within the router's DHCP scope, which typically includes 192.168.1.2 to 192.168.1.254 unless modified. This can cause an IP conflict if the router assigns that address to another device.

Practice this question →
28
MCQhard

A technician is configuring a router with two interfaces: WAN (DHCP from ISP) and LAN (static IP 10.0.0.1/24). The technician sets the LAN subnet mask to 255.255.255.0. A workstation is assigned IP 10.0.0.100/24 and can ping the router, but cannot access the internet. The router's WAN interface has IP 203.0.113.5/30. What is the most likely missing configuration?

A.The workstation's default gateway is set to 10.0.0.1.
B.The router lacks a default route pointing to the ISP's gateway.
C.The WAN subnet mask should be 255.255.255.0.
D.The LAN subnet mask should be 255.255.0.0.
AnswerB

Without a default route, the router does not know where to send traffic destined for the internet, even though it has a WAN IP.

Why this answer

The workstation can reach the router, so the LAN is fine. The router has a WAN IP, but without a default route (or NAT), traffic from the LAN cannot be forwarded to the internet. The /30 WAN subnet only has two usable IPs, so the router needs a route to the ISP's next hop.

This tests routing and NAT concepts.

Practice this question →
29
MCQmedium

A technician is troubleshooting a network where a user cannot access the internet. The user's workstation has an IP of 192.168.1.15, subnet mask 255.255.255.0, and default gateway 192.168.1.1. The technician pings 192.168.1.1 successfully but cannot ping 8.8.8.8. What is the most likely cause?

A.The workstation's subnet mask is incorrect.
B.The router's WAN connection is down or misconfigured.
C.The DNS server is not configured on the workstation.
D.The workstation's IP address is a duplicate.
AnswerB

Correct. Since local connectivity works but external fails, the router likely has no internet connection.

Why this answer

Successful ping to the gateway indicates local network connectivity is fine. Failure to ping an external IP like 8.8.8.8 suggests the router cannot reach the internet, possibly due to an ISP issue or misconfigured WAN settings.

Practice this question →
30
MCQmedium

A technician is troubleshooting a network where a user cannot access a web server at 10.0.0.50. The user's workstation has an IP of 10.0.0.25 with a subnet mask of 255.255.255.0. The technician pings 10.0.0.50 and gets a reply, but the web page does not load. What should the technician check next?

A.Verify the default gateway on the workstation.
B.Check if the web server's firewall is blocking HTTP/HTTPS traffic.
C.Change the workstation's IP address to a different subnet.
D.Replace the network cable between the workstation and switch.
AnswerB

Correct. A firewall can block specific ports while allowing ICMP (ping), so checking port access is appropriate.

Why this answer

Since ping succeeds, Layer 3 connectivity (IP) is working. The issue is likely at Layer 4 (transport) or above, such as a firewall blocking the web port (80/443) or a misconfigured web server.

Practice this question →

Ready to test yourself?

Try a timed practice session using only IP Addressing questions.

Start 20-question session