CompTIA Network+ Certification Exam
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:
IP address: 10.10.150.16
Subnet mask: 255.255.255.240
Default gateway: 10.10.150.32
Speed: 1000 Mbps
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
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.
After recent changes to the pictured network, several users are unable to access the servers. Only PC1, PC2, PC3, and PC4 are clickable and will give you access to the command prompt and the adapter configuration tabs.
Verify the settings by using the command prompt, after making any system changes. Next, restore connectivity by making the appropriate changes to the infrastructure. When you have completed these steps, select the Done button to submit.
On PC3, change the subnet mask to 255.255.255.0. When it is set to 255.255.255.128, then the PC with a .129 address will not be on the same subnet as the default gateway which is .1 On PC4, change the default gateway to 10.0.2.1. It has been incorrectly set as 10.1.2.1.
The default gateway must be on the same network as the nodes that use it. Therefore, the subnet on PC3 and the default gateway on PC4 must be modified.
Dulaney, Emmett and Mike Harwood, CompTIA Network+ Authorized Exam Cram, Fourth Edition, Pearson, Indianapolis, 2012, p 101.
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
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.
A network administrator recently installed a web proxy server at a customer’s site. The following week, a system administrator replaced the DNS server overnight. The next day, customers began having issues accessing public websites. Which of the following will resolve the issue?
A. Update the DNS server with the proxy server information.
B. Implement a split horizon DNS server.
C. Reboot the web proxy and then reboot the DNS server.
D. Put the proxy
server on the other side of the demarc.
Correct Answer: A
Proxy servers act as an intermediary for requests from clients seeking resources from other servers. If the DNS server is not communicating with the proxy server, these requests are not forwarded. Therefore, updating the DNS server with the proxy server information will solve the problem.
Two weeks after installation, a network technician is now unable to log onto any of the newly installed company switches. The technician suspects that a malicious user may have changed the switches’ settings before they were installed in secure areas. Which of the following is the MOST likely way in which the malicious user gained access to the switches?
A. Via SSH using the RADIUS shared secret
B. Via HTTP using the default username and password
C. Via console using the administrator’s password
D. Via SNMP using the default RO community
Correct Answer: B
A new network switch is accessed via HTTP to perform the initial configuration. The username and password used is a factory default.
A network technician is troubleshooting a problem at a remote site. It has been determined that the connection from router A to router B is down. The technician at the remote site re-terminates the CAT5 cable that connects the two routers as a straight through cable. The cable is then tested and is plugged into the correct interface. Which of the following would be the result of this action?
A. The normal amount of errors and the connection problem has been resolved.
B. The interface status will indicate that the port is administratively down.
C. The traffic will flow, but with excessive errors.
D. The interface status will show line protocol down.
Correct Answer: D
Devices of different types are connected with a straight through cable (patch cable). In this case, it is used to connect two devices of the same type. It is for this reason that the interface will display the line protocol down status.
Which of the following helps prevent routing loops?
A. Routing table
B. Default gateway
C. Route summarization
D. Split horizon
Correct Answer: D
Routing loops occur when the routing tables on the routers are slow to update and a redundant communication cycle is created between routers. Split horizon, which prevents the router from advertising a route back to the other router from which it was learned, can be used to resist routing loops. Poison reverse, also known as split horizon with poison reverse, is also used to resist routing loops.
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
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.
Which of the following WAN technologies is associated with high latency?
Correct Answer: B
Latency in this instance is the time it takes for the signal to and from the satellite. Since signal has to travel to the satellite, then from the satellite to the ground station, and then out to the Internet (or I
P WAN). Not forgetting the return trip, and processing delays.
When a client calls and describes a problem with a computer not being able to reach the Internet, in which of the following places of the OSI model would a technician begin troubleshooting?
A. Transport layer
B. Physical layer
C. Network layer
D. Session layer
Correct Answer: B
The bottom layer of the OSI reference model is Layer 1, the physical layer.
The physical layer is the layer that defines the hardware elements of a network.
These elements include:
Network Interface Cards
The type of signals used for data transmissions
When troubleshooting a network connectivity issue, the first thing you would check is the computer’s network cabling, the network card etc. In other words, the computer’s physical connection to the network.