Your Networking Q&A, Simplified by NB
Here you’ll find expert answers to all the networking questions we post on our LinkedIn page. Stay updated, learn from real discussions, and strengthen your networking skills with Network Bulls!”
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Ques - 1 |
Your manager asks you which service is responsible for translating the source IP address of a packet to the IP address of the public interface on the router? (A) DHCP |
| Answer | (B) NAT is responsible for translating the source IP address of a packet to use the IP of the public interface on the NAT device. |
| Ques. - 2 |
Which network service can be configured on your router that is responsible for assigning IP addresses to systems on the network? (A) DHCP |
| Answer | (A) DHCP The DHCP service is responsible for assigning IP addresses automatically to systems on the network. |
| Ques - 3 |
What service on the network is responsible for converting the FQDN to an IP address? (B) DNS server |
| Answer |
(B)DNS DNS is responsible for converting the friendly name, such as www.gleneclarke.com, to an IP address. |
| Ques - 4 |
You are monitoring network traffic and you notice a number of DHCP discover messages on the network. Which of the following is the destination address of the DHCP discover message? (A) 0F-1B-3C-2F-3C-2A(B) FF-FF-FF-FF-FF-FF (C) 192.168.4.5 (D) 192.168.0.0 |
| Answer |
(B) FF-FF-FF-FF-FF-FF The DHCP discover message is a broadcast message which is used to locate the DHCP server on the network. FF-FF-FF-FF-FF-FF is the layer-2 representation of a broadcast address |
| Ques - 5 |
When a client system boots up and requests an IP address, it first must send out which message? (A) DHCP request |
| Answer |
(B). DHCP discover The DHCP discover message is the first message sent out by a DHCP client to locate a DHCP server on the network. The DHCP discover message is a broadcast message which has a destination MAC address of FF-FF-FF-FF-FF-FF. |
| Ques - 6 |
Which of the following is a layer-3 device? |
| Answer |
(B). Router |
| Ques - 7 | A group of systems that can receive one another’s broadcast messages is known as a __________________. (A) Collision domain (B) Active directory domain (C) Fully qualified domain name (D) Broadcast domain |
| Answer |
(D)- Broadcast domain |
| Ques - 8 |
A group of systems that can have their data collide with one another is known as a ____________________. |
| Answer |
(C). Collision domain |
| Ques - 9 |
What layer of the OSI model is responsible for breaking the data into smaller segments? |
| Answer | (D). Transport The transport layer is responsible for breaking the data into smaller chunks called segments. |
| Ques - 10 | Which layer of the OSI model is responsible for routing and logical addressing? (A) Network (B) Physical (C) Data link (D) Transport |
| Answer | (A). Network The network layer is responsible for logical addressing and routing. |
| Ques - 11 | Which of the following are considered layer-2 devices? (Choose two.) (A) Bridge (B) Router (C) Repeater (D) Switch (E) Hub |
| Answer | (A). Bridge, (D). Switch Both bridges and switches run at layer 2 and are devices that filter traffic by the MAC address. |
| Ques - 12 | Which of the following are considered layer-1 devices? (Choose two.) (A) Bridge (B) Router (C) Repeater (D) Switch (E) Hub |
| Answer | (C). Repeater, (E). Hub A hub and a repeater are examples of layer-1 devices. Remember that a layer-1 device works with the electrical signal. |
| Ques - 13 | What is the application layer protocol for receiving e-mail over the Internet? (A) FTP (B) SMTP (C) SNMP (D) POP3 |
| Answer | ( D). POP3 POP3 is the Internet protocol for receiving e-mail, whereas SMTP is the Internet protocol for delivering e-mail. |
| Ques - 14 | Which Gigabit Ethernet standard uses UTP cabling to reach 1000 Mbps? (A) 1000BaseTX (B) 1000BaseSX (C) 1000BaseCX (D) 1000BaseLX |
| Answer | (A). 1000BaseTX The Gigabit Ethernet standard that uses UTP cabling is 1000BaseTX. |
| Ques - 15 | Which of the following addresses does a router use to determine where a packet needs to be delivered? (Choose two.) (A) 24.56.78.10 (B) 00-3B-4C-2B-00-AF (C) A layer-3 address (D) A layer-2 address |
| (A). 24.56.78.10 (C). A layer-3 address Routers use layer-3 addresses to determine where to send a packet. |
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| Ques - 16 | What type of cable would you use if you wanted to connect a system to an RJ-45 port on a switch? (A) Fiber (B) Crossover (C) Straight-through (D) Thinnet |
| Answer | Ans (C). Straight-through Straight-through cables are used to connect dissimilar devices such as a computer to a switch or a router to a switch. |
| Ques - 17 | You wish to network two systems by connecting a computer directly to another computer.Which type of cable would you use? (A) Fiber (B) Crossover (C) Straight-through (D) Thinnet |
| Answer | (B). Crossover To connect two systems directly together, you use a crossover cable. |
| Ques - 18 | You are testing communication to a router and have decided to connect your workstation to the Fast Ethernet port of the router. What type of cable would you use? (A) Fiber (B) Crossover (C) Straight-through (D) Thinnet |
| Answer | (B). Crossover This is a strange question because you typically would not do this, but it is on the exam. In this example, the router and workstation are both “hosts” on the network, so you can consider them similar devices; similar devices are connected with a crossover cable. |
| Ques - 19 | You have a UTP cable that has been configured at both ends with the 568B standard. What type of cable is it? (A) Straight-through (B) Crossover (C) Rollover (D) Coax |
| Answer | (A). Straight-through A straight-through cable is wired the same at both ends of the cable. |
| Ques - 20 | You wish to create a crossover cable and have wired one end of the cable with the 568A standard, What standard should you use to wire the opposite end of the cable? (A) 568B (B) 568A (C) 569B (D) 569A |
| Answer | (A). 568B To create a crossover cable, you wire one end of the cable with 568A and the other end of the cable with 568B. |
| Ques - 21 | Which of the following are considered class A addresses? (Select all that apply.) (A) 129.45.10.15 (B) 10.35.87.5 (C) 131.15.10.12 (D) 192.156.8.34 (E) 121.59.87.32 (F) 210.45.10.112 |
| Answer | (B). 10.35.87.5 (E). 121.59.87.32 Class A addresses have a value in the first octet that ranges from 1 to 127. Class B addresses have a value in the first octet that ranges from 128 to 191. Class C addresses have a value in the first octet that ranges from 192 to 223. |
| Ques - 22 | Sue is reviewing IP addressing basics and asks you which of the following is considered a Class A private address. (A) 24.56.10.12 (B) 192.168.0.5 (C) 172.16.45.10 (D) 10.55.67.99 |
| Answer | (D). 10.55.67.99 Class A private addresses start with 10.0.0.0. Note that class B private addresses range from 172.16.0.0 up to 172.31.255.255. Class C private addresses range from 192.168.0.0 to 192.168.255.255. |
| Ques. 23 | What is the default subnet mask of a system with the IP address of 189.34.5.67? (A) 255.0.0.0 (B) 255.255.0.0 (C) 255.255.255.0 (D) 255.255.255.255 |
| Answer | (B). 255.255.0.0 With 189 as the value of the first octet, this address is a class B address, which has a default subnet mask of 255.255.0.0 |
| Ques. 24 | Are the systems of 201.45.3.56 and 201.45.5.20 on the same network? (A) Yes (B) No |
| Answer | (B). No Because the IP address starts with 201, it means that it is a class C address. Class C addresses use the first three octets as the network ID, so any system on the same The network would have the same first three numbers in the IP address. |
| Ques. 25 | Which of the following addresses are considered invalid addresses to assign to a host on the network? (Select all that apply.) (A) 10.254.255.255 (B) 120.127.34.10 (C) 190.34.255.255 (D) 136.45.68.22 (E) 202.45.6.0 (F) 127.87.3.22 |
| Answer | C. 190.34.255.255 E. 202.45.6.0 F. 127.87.3.22 You cannot assign an IP address to a system that has all host bits set to 1s or all host bits set to 0. You also cannot have an IP address where the first octet is 127, which is reserved for loopback. |
| Ques. 26 | The decimal number of 137 is which of the following in binary? (A) 10001001 (B) 10101001 (C) 11001001 (D) 10000101 |
| Answer | A. 10001001 To convert the decimal number to binary, you would enable the bits that hold the values of 128+8+1=137 |
| Ques. 27 | Are the systems with the IP addresses of 121.56.78.10/8 and 121.45.6.88/8 on the same network? (A) Yes (B) No |
| Answer | A. Yes Looking at the first address, you can see that the value of the first octet is 121, which makes the address a class A address. Class A addresses have the network ID as the first octet, so if another system has the same first octet then it is on the same network |
| Ques. 28 | The binary number of 01101101 is which of the following decimal values? (A) 101 (B) 109 (C) 135 (D) 143 |
| Answer | (B). 109 To convert this binary value to decimal, you take the value of each bit set to 1 and add them together (64+32+8+4+1=109) |
| Ques. 29 | Which class address always has the value of the first bits in the IP address set to 110? (A) Class A (B) Class B (C) Class C (D) Class D |
| Answer | (C). Class C Class C addresses always have the first three bits set to 110. This means that a class C address ranges from 11000000 (192) to 11011111 (223). |
| Ques. 30 | Which IP address class always has the first bit in the address set to 0? (A) Class A (B) Class B (C) Class C (D) Class D |
| Answer | (A). Class Class A addresses always have the first bit of the IP address set to 0. This means that class A addresses range from 00000001 (1) to 01111111 (127). |
| Ques. 31 | Which protocol is responsible for converting the logical address to a physical address? (A) TCP (B) IP (C) ICMP (D) ARP |
| Answer | (D). ARP Address Resolution Protocol (ARP) is a network layer protocol that converts the IP address ( logical address) to a MAC address (physical address) |
| Ques. 32 | The ARP request is sent to which of the following layer-2 destination addresses? (A) FF-FF-FF-FF-FF-FF (B) 192.168.0.255 (C) 00-FF-00-FF-00-FF (D) 00-00-00-00-00-00 |
| Answer | Ans (A). FF-FF-FF-FF-FF-FF The ARP request message is a broadcast message and is therefore destined for the broadcast address of FF-FF-FF-FF-FF-FF |
| Ques. 33 | What are the three phases of the TCP three-way handshake? (A) ACK/SYN, SYN, ACK (B) SYN, ACK/SYN, ACK (C) ACK/SYN, ACK, SYN (D) SYN, ACK, SYN/ACK |
| Answer | (B). SYN, ACK/SYN, ACK The TCP three-way handshake starts with a SYN message from computer A to computer B. Computer B then sends an ACK/SYN message, which is then followed by computer A sending an ACK. |
| Ques. 34 | Which of the following does TCP use to guarantee delivery? (A) Source and destination IP address (B) Source and destination port (C) Sequence numbers and acknowledgments (D) Sequence numbers and ports |
| Answer | (C). Sequence numbers and acknowledgments TCP assigns each message (known as a segment) a sequence number. When a message is received at the destination, it sends an acknowledgment based on the received sequence number indicating that the message has been received. |
| Ques. 35 | What TCP/IP protocol is responsible for logical addressing and routing functions? (A) TCP (B) IP (C) ICMP (D) UDP |
| Answer | (B). IP The Internet Protocol (IP) protocol is responsible for logical addressing and routing functions. The IP protocol runs at the network layer. |
| Ques. 36 | Which transport layer protocol is responsible for unreliable delivery? (A) TCP (B) IP (C) ICMP (D) UDP |
| Answer | (D). UDP User Datagram Protocol (UDP) is responsible for unreliable delivery, which means it does not track whether the data has been received at the destination. |
| Ques. 37 | Which TCP/IP protocol is responsible for error and status reporting? (A) TCP (B) IP (C) ICMP (D) UDP |
| Answer | (C). ICMP Internet Control Message Protocol (ICMP) is responsible for error and status reporting and runs at the network layer of the OSI model |
| Ques. 38 | The router looks at which field in the IP header to decide where to send the packet? (A) Source IP address (B) Destination IP address (C) Source MAC address (D) Destination MAC address |
| Answer | (B). Destination IP address When a router receives a packet, it compares the destination IP address in the IP header against the routing table to determine where to send the packet |
| Ques.39 | What flags are set on the second phase of the three-way handshake? (A) FIN/SYN (B) ACK/FIN (C) ACK/SYN (D) ACK/RST |
| Answer | (C). ACK/SYN |
| Ques. 40 | Which flag is set in a TCP packet that indicates a previous packet was received? (A) PSH (B) FIN (C) ACK (D) RST |
| Answer | C. ACK The acknowledgement flag (ACK) is set on a packet to indicate that the message is confirming a previous packet has been received. |
| Ques. 41 | You wish to allow echo request messages to pass through the firewall. What ICMP type is used in an echo request message? (A) 0 (B) 8 (C) 3 (D) 11 |
| Answer | B. 8 ICMP type 8 is used for echo requests, whereas echo reply messages are ICMP type 0 |
| Ques. 42 | Which of the following are fields found in the IP header? (Select all that apply.) (A) Sequence number (B) Destination port (C) Source IP address (D) Type (E) Time to Live (F) SYN flag |
| Answer | C. Source IP address E. Time to Live The IP header contains information used by the IP protocol. Things such as the source and destination IP address, along with the TTL, are stored in the IP header. Source and destination port information are stored in the TCP or UDP header, and sequence numbers and acknowledgements are stored in the TCP header. |
| Ques. 43 | Which of the following are considered application-layer protocols? (A) TCP (B) IP (C) FTP (D) ICMP |
| Answer | C. FTP FTP is an example of an application-layer protocol. IP and ICMP are network layer protocols, whereas TCP is a transport layer protocol. For the CCNA exams, you must know the layers of the OSI model and what protocols run at those layers. |
| Ques. 44 | Which transport layer protocol is responsible for reliable delivery? (A) UDP (B) ICMP (C) IP (D) TCP |
| Answer | D. TCP TCP is responsible for reliable delivery. Note that UDP is a transport-layer protocol, but It is used for unreliable delivery. |
| Ques. 45 | What ICMP type is used by the echo reply message? (A) 0 (B) 3 (C) 5 (D) 8 |
| Answer | A. 0 The echo reply message uses ICMP type 0. Note that echo request messages use ICMP type 8. |
| Ques. 46 | The security administrator for your network has asked that you block ping messages from entering your network. What protocol would you block? (A) ICMP (B) IP (C) TCP (D) UDP |
| Answer | A. ICMP ICMP is the protocol used by the ping command, so to block pings you need to block ICMP. |
| Ques. 47 | Which TCP flag is responsible for dropping a connection at any point in time? (A) PSH (B) FIN (C) ACK (D) RST |
| Answer | D. RST A reset flag (RST) is used to drop the TCP connection at any time. |
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