CompTIA Security+ Question I-9

Which of the following IP addresses would be hosts on the same subnet given the subnet mask 255.255.255.224? (Select TWO).

A. 10.4.4.125
B. 10.4.4.158
C. 10.4.4.165
D. 10.4.4.189
E. 10.4.4.199

Answer: C,D

Explanation:
With the given subnet mask, a maximum number of 30 hosts between IP addresses 10.4.4.161 and 10.4.4.190 are allowed. Therefore, option C and D would be hosts on the same subnet, and the other options would not.

References: http://www.subnetonline.com/pages/subnet-calculators/ip-subnet-calculator.php

CompTIA Security+ Question A-63

Which of the following would the security engineer set as the subnet mask for the servers below to utilize host addresses on separate broadcast domains?
Server 1: 192.168.100.6
Server 2: 192.168.100.9
Server 3: 192.169.100.20

A. /24
B. /27
C. /28
D. /29
E. /30

Answer: D

Explanation:
Using this option will result in all three servers using host addresses on different broadcast domains.

CompTIA Network+ Question C-54

A PC technician has installed a new network printer that was preconfigured with the correct static IP address, subnet mask, and default gateway. The printer was installed with a new cable and appears to have link activity, but the printer will not respond to any network communication attempts. Which of the following is MOST likely the cause of the problem?

A. Damaged cable
B. Duplex mismatch
C. Incorrect VLAN assignment
D. Speed mismatch

Correct Answer: C

Explanation:
If a port is accidentally assigned to the wrong VLAN in a switch, it’s as if that client was magically transported to another place in the network. This would explain the inability to communication with the printer, as it is on a different VLAN.

CompTIA Network+ Question C-33

While troubleshooting a connectivity issue, a network technician determines the IP address of a number of workstations is 169.254.0.0/16 and the workstations cannot access the Internet. Which of the following should the technician check to resolve the problem?

A. Default gateway address
B. Misconfigured DNS
C. DHCP server
D. NIC failure

Correct Answer: C

Explanation:
If a DHCP server fails, the workstations are assigned an address from the 169.254.0.0 address range by Automatic Private IP Addressing (APIPA). APIPA also configures a suitable subnet mask, but it doesn’t configure the system with a default gateway address. This allows communication on the local network, but not externally.

CompTIA Network+ Question C-11

A network technician has been assigned to install an additional router on a wireless network. The router has a different SSID and frequency. All users on the new access point and the main network can ping each other and utilize the network printer, but all users on the new router cannot get to the Internet. Which of the following is the MOST likely cause of this issue?

A. The gateway is misconfigured on the new router.
B. The subnet mask is incorrect on the new router.
C. The gateway is misconfigured on the edge router.
D. The SSID is incorrect on the new router.

Correct Answer: A

Explanation:
A missing or incorrect default gateway parameter limits communication to the local segment.
The question states: “All users on the new access point and the main network can ping each other and utilize the network printer, but all users on the new router cannot get to the Internet”.

CompTIA Network+ Question B-70

After repairing a computer infected with malware, a technician determines that the web browser fails to go to the proper address for some sites. Which of the following should be checked?

A. Server host file
B. Subnet mask
C. Local hosts file
D. Duplex settings

Correct Answer: C

Explanation:
The local hosts file is a text file that contains hostname-to-IP address mappings. By default, host to IP address mappings that are configured in the Hosts file supersede the information in DNS. If there is an entry for a domain name in the Hosts file, then the server will not attempt to query DNS servers for that name. Instead, the IP address that is configured in the Hosts file will be used. If the IP address corresponding to a name changes and the Hosts file is not updated, you may be unable to connect to the host.

CompTIA Network+ Question B-49

A technician, Peter, has been tasked with assigning two IP addresses to WAN interfaces on connected routers. In order to conserve address space, which of the following subnet masks should Peter use for this subnet?

A. /24
B. /32
C. /28
D. /29
E. /30

Correct Answer: E

Explanation:
An IPv4 address consists of 32 bits. The first x number of bits in the address is the network address and the remaining bits are used for the host addresses. The subnet mask defines how many bits form the network address and from that, we can calculate how many bits are used for the host addresses.
In this question, the /30 subnet mask dictates that the first 30 bits of the IP address are used for network addressing and the remaining 2 bits are used for host addressing. The formula to calculate the number of hosts in a subnet is 2n – 2. The “n” in the host’s formula represents the number of bits used for host addressing. If we apply the formula (22 – 2), a /30 subnet mask will provide 2 IP addresses.

CompTIA Network+ Question B-38

A host has been assigned the address 169.254.0.1. This is an example of which of the following address types?

A. APIPA
B. MAC
C. Static
D. Public

Correct Answer: A

Explanation:
APIPA stands for Automatic Private IP Addressing and is a feature of Windows operating systems. When a client computer is configured to use automatic addressing (DHCP), APIPA assigns a class B IP address from 169.254.0.0 to 169.254.255.255 to the client when a DHCP server is unavailable.
When a client computer configured to use DHCP boots up, it first looks for a DHCP server to provide the client with IP address and subnet mask. If the client is unable to contact a DHCP server, it uses APIPA to automatically configure itself with an IP address from a range that has been reserved especially for Microsoft. The client also configures itself with a default class B subnet mask of 255.255.0.0. The client will use the self-configured IP address until a DHCP server becomes
available.

CompTIA Network+ Question B-15

A company has changed ISPs for their office and ordered a new 250 Mbps symmetrical Internet connection. As a result, they have been given a new IP range. The ISP has assigned the company 10.10.150.16 /28. The company gateway router has the following interface configuration facing the ISP:
Interface A:
IP address: 10.10.150.16
Subnet mask: 255.255.255.240
Default gateway: 10.10.150.32
Speed: 1000 Mbps Duplex: Auto
State: No Shutdown

None of the workstations at the company are able to access the Internet. Which of the following are the reasons? (Select TWO).

A. There is a duplex mismatch between the router and ISP.
B. The router interface is turned off.
C. The interface is set to the incorrect speed.
D. The router is configured with the incorrect subnet mask.
E. The router interface is configured with the incorrect IP address.
F. The default gateway is configured incorrectly.

Correct Answer: EF

Explanation:
According to the IP Address Range Calculator, for the given subnet mask and the IP range address range assigned by the ISP, the first host address should be 10.10.150.17 and the broadcast address should be 10.10.150.31. Therefore, the router interface is configured with the incorrect IP address and the default gateway is configured incorrectly.