Q4: Core Concepts

Question 1

Used to resolve an IP address into MAC address.

A. ARP
B. Gratuitous ARP
C. RARP
D. DNS

Answer 1

Answer:
c) ARP

Explanation: ARP (address resolution protocol) is the protocol that is used to discover the mac address of a host if the IP address is known.

Question 2

Host1 MAC = AAAA.AAAA.AAAA
Host2 MAC = BBBB.BBBB.BBBB
Host3 MAC = CCCC.CCCC.CCCC

Host1 wants to send data to Host2, but does not have Host2’s mac address in its ARP table. What would be the destination address for an ARP packet sent in the following scenario?

A. BBBB.BBBB.BBBB
B. BBBB.BBBB.BBBB & CCCC.CCCC.CCCC
C. FFFF.FFFF.FFFF
D. 0000.0000.0000

Answer 2

Answer:
c) FFFF.FFFF.FFFF

Explanation: When the mac address of the destination is not know, the host will broadcast an ARP onto the network trying to find the host with the identified IP address. The destination address of a broadcast onto a local LAN is FFFF.FFFF.FFFF

Question 3

Briefly describe the function of DNS.

Answer 3

Explanation: DNS, or Domain Name Service is a service that translates the url you type into your web broswer into a destination IP address. It would be virtually impossible to remember all the IP addresses for the websites each of us visit. It would also be extremely annoying to have to pull out a “phone book” of sorts that contains the IP addresses and urls of entities on the Internet and manually look up the IP addess to enter into your web browser. Instead, DNS servers take care of this automatically by supplying the IP address representing the url after you press on your web browser.

Question 4

Where can a DNS server be located?

A. only on the local network
B. on the local network or the Internet
C. only on the Internet
D. none of the above

Answer 4

Answer
b) On the local network or the Internet

Explanation: DNS servers can be managed and hosted internally by a network administrator. There are also public DNS servers on the Internet that are maintained by other entities. One of Google’s DNS servers = 8.8.8.8

Question 5

There is a monthly or annual cost for subscribing to a public DNS such as Google DNS.

A. TRUE
B. FALSE

Answer 5

Answer:
b)FALSE

Explanation: There is no cost or subscription required to use public DNS servers, such as Google’s DNS.