- (Topic 3)
Which of the following best describes what an organization would use port address translation for?
Correct Answer:
B
The best answer is B. Public address on the perimeter router.
Port address translation (PAT) is a function that allows multiple users within a private network to make use of a minimal number of IP addresses. Its basic function is to share a single IP public address between multiple clients who need to use the Internet publicly. It is an extension of network address translation (NAT)1.
PAT works by creating dynamic NAT mapping, in which a global (public) IP address and a unique port number are selected. The router keeps a NAT table entry for every unique combination of the private IP address and port, with translation to the global address and a unique port number2.
Therefore, an organization would use PAT for having a public address on the perimeter router, which can be shared by many hosts on the private network using different port numbers. This can reduce the bandwidth consumption and cost of the organization’s internet connection, as well as provide some security benefits by hiding the internal network structure3.
The other options are not correct because:
✑ VLANs on the perimeter are not related to PAT, as they are used to segment the network into logical groups based on different criteria, such as function, security, or performance4.
✑ Non-routable address on the perimeter router would not allow the organization to access the Internet or the cloud, as non-routable addresses are not valid on the public network and cannot be translated by PAT5.
✑ Servers on the perimeter are not a reason to use PAT, as servers usually have static IP addresses and do not need to share a public address with other hosts. Servers on the perimeter may use NAT, but not PAT, to map their private IP addresses to a public IP address2.
- (Topic 3)
Which of the following can be used to limit the ability of devices to perform only HTTPS connections to an internet update server without exposing the devices to the public internet?
Correct Answer:
A
An internal proxy server is a server that acts as an intermediary between internal devices and external servers on the internet. An internal proxy server can be used to limit the ability of devices to perform only HTTPS connections to an internet update server by filtering and forwarding the requests and responses based on predefined rules or policies. An internal proxy server can also prevent the devices from being exposed to the public internet by hiding their IP addresses and providing a layer of security and privacy.
- (Topic 3)
A network technician is selecting a replacement for a damaged fiber cable that goes directly to an SFP transceiver on a network switch. Which of the following cable connectors should be used?
Correct Answer:
C
- (Topic 1)
A workstation is configured with the following network details:
Software on the workstation needs to send a query to the local subnet broadcast address. To which of the following addresses should the software be configured to send the query?
Correct Answer:
D
The software on the workstation should be configured to send the query to 10.1.2.255, which is the local subnet broadcast address. A broadcast address is a special address that allows a device to send a message to all devices on the same subnet. It is usually derived by setting all the host bits to 1 in the network address. In this case, the network address is 10.1.2.0/27, which has 27 network bits and 5 host bits. By setting all the host bits to 1, we get 10.1.2.31 as the broadcast address in decimal notation, or 10.1.2.255 in dotted decimal notation. References: https://www.cisco.com/c/en/us/support/docs/ip/routing-information-protocol-rip/13788- 3.html
- (Topic 1)
Which of the following would need to be configured to ensure a device with a specific MAC address is always assigned the same IP address from DHCP?
Correct Answer:
B
A reservation should be configured to ensure a device with a specific MAC address is always assigned the same IP address from DHCP. A reservation is a feature of DHCP that allows an administrator to assign a fixed IP address to a device based on its MAC address. This way, the device will always receive the same IP address from the DHCP server, even if it is powered off or disconnected from the network for a long time. References: https://docs.microsoft.com/en-us/windows-server/troubleshoot/configure-dhcp- reservations
