Computer Networks MCQ Set 1
1. Network layer firewall works as a
a) Frame filter
b) Packet filter
c) Both Frame as well as Packet filter
d) None of the mentioned
Answer
Answer: b [Reason:] As you know, firewalls are available as hardware appliances, as software-only, or a combination of the two. In every case, the purpose of a firewall is to isolate your trusted internal network (or your personal PC) from the dangers of unknown resources on the Internet and other network connections that may be harmful. The firewall prevents unauthorized access to your internal, trusted network from outside threats.
2. Network layer firewall has two sub-categories as
a) State full firewall and stateless firewall
b) Bit oriented firewall and byte oriented firewall
c) Frame firewall and packet firewall
d) None of the mentioned
Answer
Answer: a [Reason:] Most network layer firewalls can operate as stateful or stateless firewalls, creating two subcategories of the standard network layer firewall. Stateful firewalls have the advantage of being able to track packets over a period of time for greater analysis and accuracy — but they require more memory and operate more slowly. Stateless firewalls do not analyze past traffic and can be useful for systems where speed is more important than security, or for systems that have very specific and limited needs. For example, a computer that only needs to connect to a particular backup server does not need the extra security of a stateful firewall.
3. A firewall is installed at the point where the secure internal network and untrusted external network meet which is also known as __________
a) Chock point
b) Meeting point
c) Firewall point
d) Secure point
Answer
Answer: a [Reason:] A firewall can be a PC, a router, a midrange, a mainframe, a UNIX workstation, or a combination of these that determines which information or services can be accessed from the outside and who is permitted to use the information and services from outside. Generally, a firewall is installed at the point where the secure internal network and untrusted external network meet, which is also known as a chokepoint.
4. Which of the following is / are the types of firewall?
a) Packet Filtering Firewall
b) Dual Homed Gateway Firewall
c) Screen Host Firewall
d) All of the mentioned
Answer
Answer: a [Reason:] A firewall can be a PC, a midrange, a mainframe, a UNIX workstation, a router, or combination of these. Depending on the requirements, a firewall can consist of one or more of the following functional components: Packet-filtering router
5. A proxy firewall filters at?
a) Physical layer
b) Data link layer
c) Network layer
d) Application layer
Answer
Answer: d [Reason:] The application firewall is typically built to control all network traffic on any layer up to the application layer. It is able to control applications or services specifically, unlike a stateful network firewall, which is – without additional software – unable to control network traffic regarding a specific application. There are two primary categories of application firewalls, network-based application firewalls and host-based application firewalls.
6. A packet filter firewall filters at?
a) Physical layer
b) Data link layer
c) Network layer or Transport layer
d) Application layer
Answer
Answer: c [Reason:] In computing, a firewall is a network security system that monitors and controls the incoming and outgoing network traffic based on predetermined security rules.[1] A firewall typically establishes a barrier between a trusted, secure internal network and another outside network, such as the Internet, that is assumed not to be secure or trusted.[2] Firewalls are often categorized as either network firewalls or host-based firewalls.
7. What is one advantage of setting up a DMZ with two firewalls?
a) You can control where traffic goes in three networks
b) You can do stateful packet filtering
c) You can do load balancing
d) Improved network performance
Answer
Answer: c [Reason:] In a topology with a single firewall serving both internal and external users (LAN and WAN), it acts as a shared resource for these two zones.
8. What tells a firewall how to reassemble a data stream that has been divided into packets?
a) The source routing future
b) The number in the header’s identification field
c) The destination IP address
d) The header checksum field in the packet header
Answer
Answer: a [Reason:] source routing future.
9. A stateful firewall maintains a ___________ which is a list of active connections?
a) Routing table
b) Bridging table
c) State table
d) Connection table
Answer
Answer: a [Reason:] Routing table with best performance
10. A firewall needs to be __________ so that it can grow with the network it protects
a) Robust
b) Expansive
c) Fast
d) Scalable
Answer
Answer: b [Reason:] Expansive to block the fake subscribers.
Computer Networks MCQ Set 2
1. Which type of Ethernet framing is used for TCP/IP and DEC net?
a) Ethernet 802.3
b) Ethernet 802.2
c) Ethernet II
d) Ethernet SNAP
Answer
Answer: c [Reason:] Ethernet 802.3 is used with NetWare versions 2 through 3.11, Ethernet 802.2 is used withNetWare 3.12 and later plus OSI routing, Ethernet II is used with TCP/IP and DEC net,and Ethernet SNAP is used with TCP/IP and AppleTalk.
2. You are a system administrator on a NetWare network, you are runningNetWare 4.11 and you cannot communicate with your router. What is the likelyproblem?
a) NetWare 4.11 defaults to 802.2 encapsulation
b) NetWare 4.11 defaults to 802.3 encapsulation
c) Cisco routers only work with NetWare 3.11
d) NetWare 3.11 defaults to 802.2 encapsulation
Answer
Answer: a [Reason:] The default encapsulation on Cisco routers is Novell Ethernet_802.3 and NetWare 3.12and later defaults to 802.2 encapsulation, 3.11 and earlier defaults to 802.3.
3. NetWare IPX addressing uses a network number and a node number. Which statement is not true?
a) The network address is administratively assigned and can be up to 16 hexadecimal digits long
b) The node address is always administratively assigned
c) The node address is usually the MAC address
d) If the MAC address is used as the node address, then IPX eliminates the use of ARP
Answer
Answer: b [Reason:] The network address can be up to 16 hexadecimal digits in length. The node number is 12hexadecimal digits. The node address is usually the MAC address. An example IPXaddress is 4a1d.0000.0c56.de33. The network part is 4a1d. The node part is0000.0c56.de33. The network number is assigned by the system administrator of theNovell network.
4. Which NetWare protocol works on layer 3–network layer—of the OSI model?
a) IPX
b) NCP
c) SPX
d) NetBIOS
Answer
Answer: a [Reason:] IPX (Internetwork Packet Exchange) is a NetWare network layer 3 protocol used fortransferring information on LANs.
5. Which NetWare protocol provides link-state routing?
a) NLSP
b) RIP
c) SAP
d) NCP
Answer
Answer: a [Reason:] NetWare Link Services Protocol (NLSP) provides link-state routing. SAP (Service Advertisement Protocol) advertises network services. NCP (NetWare Core Protocol)provides client-to-server connections and applications. RIP is a distance vector routingprotocol.
6. As a system administrator, you want to debug IGRP but are worried that the
“debug IP IGRP transaction” command will flood the console. What is the command
that you should use?
a) Debug IP IGRP event
b) Debug IP IGRP-events
c) Debug IP IGRP summary
d) Debug IP IGRP events
Answer
Answer: d [Reason:] The “debug IP IGRP events” is used to only display a summary of IGRP routing information. You can append an IP address onto either command to see only the IGRP
updates from a neighbor.
7. What does the following series of commands accomplish? RouterIGRP 71 network
10.0.0.0 router IGRP 109 network 172.68.7.0
a) It isolates networks 10.0.0.0 and 172.68.7.0
b) It loads IGRP for networks 109 and 71
c) It disables RIP
d) It disables all routing protocols
Answer
Answer: a [Reason:] It isolates network 10.0.0.0 and 172.68.7.0 and associates autonomous systems 109 and71 with IGRP. IGRP does not disable RIP, both can be used at the same time.
8. The “IPX delay number” command will allow an administrator to change the
default settings. What are the default settings?
a) For LAN interfaces, one tick; for WAN interfaces, six ticks
b) For LAN interfaces, six ticks; for WAN interfaces, one tick
c) For LAN interfaces, zero ticks; for WAN interfaces, five ticks
d) For LAN interfaces, five ticks; for WAN interfaces, zero Ticks
Answer
Answer: a [Reason:] The default is–for LAN interfaces, one tick; for WAN interfaces, six ticks
9. As a system administrator, you need to set up one Ethernet interface on the Cisco
router to allow for both sap and Novell-ether encapsulations. Which set of
commands will accomplish this?
a) Interface Ethernet 0.1 IPX encapsulation Novell-ether IPX network 9e interface
Ethernet 0.2 IPX network 6c
b) Interface Ethernet 0 IPX encapsulation Novell-ether IPX network 9e interface
Ethernet 0 IPX encapsulation sap IPX network 6c
c) Interface Ethernet 0.1 IPX encapsulation Novell-ether interface Ethernet 0.2 IPX
encapsulation sap
d) Interface Ethernet 0.1ipx encapsulation Novell-ether IPX network 9e interface
Ethernet 0.2 IPX encapsulation sap IPX network 6c
Answer
Answer: d [Reason:] The following commands setup the sub interfaces to allow for two types of encapsulation:interface Ethernet 0.1 IPX encapsulation Novell-ether IPX network 9e interface Ethernet0.2 IPX encapsulation sap IPX network 6c.
10. What does the “IPX maximum-paths 2” command accomplish?
a) It enables load sharing on 2 paths if the paths are equal metric paths
b) It sets up routing to go to network 2
c) It is the default for Cisco IPX load sharing
d) It enables load sharing on 2 paths if the paths are unequal metric paths
Answer
Answer: a [Reason:] It enables load sharing on 2 paths if the paths are equal metric paths. The default is 1 pathand the maximum is 512 paths.
11. You want to enable both arpa and snap encapsulation on one router interface.
How do you do this?
a) The interface can handle multiple encapsulation types with no extra configuration
b) Assign two network numbers, one for each encapsulation type
c) Enable Novell-ether to run multiple encapsulation types
d) Both arpa and snap are enabled by default so you don’t have to configure anything
Answer
Answer: b [Reason:] To assign multiple network numbers, you usually use sub interfaces. A sample configuration follows: IPXEthernet 0.1 IPX encapsulation novell-ether ipx network 9e interface ethernet 0.2 ipx encapsulation sap ipx network 6c
12. By default, Cisco routers forward GNS SAPs to remote networks.
a) False
b) True
Answer
Answer: a [Reason:] GNS is Novell’s protocol to Get Nearest Server. If there is a server on the local network,that server will respond. If there isn’t, the Cisco router has to be configured to forward theGNS SAP.
13. To prevent Service Advertisements (SAPs) from flooding a network, Cisco routers
do not forward them. How are services advertised to other networks?
a) Each router builds its own SAP table and forwards that every 60 seconds
b) Each router assigns a service number and broadcasts that
c) SAPs aren’t necessary with Cisco routers
d) Cisco routers filter out all SAPs
Answer
Answer: a [Reason:] Cisco routers build SAP tables and forward the table every 60 seconds. All SAPs can’t befiltered even with 4.x since NDS and time synchronization uses SAPs.
14. Novell’s implementation of RIP updates routing tables every _________ seconds.
a) 60
b) 90
c) 10
d) 30
Answer
Answer: a [Reason:] Novell’s RIP updates routing tables every 60 seconds, Apple’s RTMP is every 10 seconds, routers ARP every 60 seconds, IGRP signal every 90 seconds, and Banyan VINES signals every 90 seconds.
15. In Novell’s use of RIP, there are two metrics used to make routing decisions.
Select the two metrics.
a) Ticks & Hops
b) Hops & Loops
c) Loops & Counts
d) Counts & Ticks
Answer
Answer: a [Reason:] It first uses ticks (which is about 1/18 sec.); if there is a tie, it uses hops; if hops are equal,then it uses an administratively assigned tiebreaker.
Computer Networks MCQ Set 3
1. The network layer concerns with
a) bits
b) frames
c) packets
d) none of the mentioned
Answer
Answer: c [Reason:] None.
2. Which one of the following is not a function of network layer?
a) routing
b) inter-networking
c) congestion control
d) none of the mentioned
Answer
Answer: d [Reason:] None.
3. The 4 byte IP address consists of
a) network address
b) host address
c) both network address & host address
d) none of the mentioned
Answer
Answer: c [Reason:] None.
4. In virtual circuit network each packet contains
a) full source and destination address
b) a short VC number
c) only source address
d) only destination address
Answer
Answer: b [Reason:] None.
5. Which one of the following routing algorithm can be used for network layer design?
a) shortest path algorithm
b) distance vector routing
c) link state routing
d) all of the mentioned
Answer
Answer: d [Reason:] None.
6. Multidestination routing
a) is same as broadcast routing
b) contains the list of all destinations
c) data is not sent by packets
d) none of the mentioned
Answer
Answer: c [Reason:] None.
7. A subset of a network that includes all the routers but contains no loops is called
a) spanning tree
b) spider structure
c) spider tree
d) none of the mentioned
Answer
Answer: a [Reason:] None.
8. Which one of the following algorithm is not used for congestion control?
a) traffic aware routing
b) admission control
c) load shedding
d) none of the mentioned
Answer
Answer: d [Reason:] None.
9. The network layer protocol of internet is
a) ethernet
b) internet protocol
c) hypertext transfer protocol
d) none of the mentioned
Answer
Answer: b [Reason:] None.
10. ICMP is primarily used for
a) error and diagnostic functions
b) addressing
c) forwarding
d) none of the mentioned
Answer
Answer: a [Reason:] None.
Computer Networks MCQ Set 4
1. The physical layer concerns with
a) bit-by-bit delivery
p) process to process delivery
c) application to application delivery
d) none of the mentioned
Answer
Answer: a [Reason:] None.
2. Which transmission media has the highest transmission speed in a network?
a) coaxial cable
b) twisted pair cable
c) optical fiber
d) electrical cable
Answer
Answer: c [Reason:] None.
3. Bits can be send over guided and unguided media as analog signal by
a) digital modulation
b) amplitude modulation
c) frequency modulation
d) phase modulation
Answer
Answer: a [Reason:] None.
4. The portion of physical layer that interfaces with the media access control sublayer is called
a) physical signalling sublayer
b) physical data sublayer
c) physical address sublayer
d) none of the mentioned
Answer
Answer: a [Reason:] None.
5. physical layer provides
a) mechanical specifications of electrical connectors and cables
b) electrical specification of transmission line signal level
c) specification for IR over optical fiber
d) all of the mentioned
Answer
Answer: d [Reason:] None.
6. In asynchronous serial communication the physical layer provides
a) start and stop signalling
b) flow control
c) both start & stop signalling and flow control
d) none of the mentioned
Answer
Answer: c [Reason:] None.
7. The physical layer is responsible for
a) line coding
b) channel coding
c) modulation
d) all of the mentioned
Answer
Answer: d [Reason:] None.
8. The physical layer translates logical communication requests from the ______ into hardware specific operations.
a) data link layer
b) network layer
c) trasnport layer
d) application layer
Answer
Answer: a [Reason:] None.
9. A single channel is shared by multiple signals by
a) analog modulation
b) digital modulation
c) multiplexing
d) none of the mentioned
Answer
Answer: c [Reason:] None.
10. Wireless transmission can be done via
a) radio waves
b) microwaves
c) infrared
d) all of the mentioned
Answer
Answer: d [Reason:] None.
Computer Networks MCQ Set 5
1. OSI stands for
a) open system interconnection
b) operating system interface
c) optical service implementation
d) none of the mentioned
Answer
Answer: a [Reason:] None.
2. The OSI model has _______ layers.
a) 4
b) 5
c) 6
d) 7
Answer
Answer: d [Reason:] None.
3. TCP/IP model does not have ______ layer but OSI model have this layer.
a) session layer
b) transport layer
c) application layer
d) None of the mentioned
Answer
Answer: a [Reason:] None.
4. Which layer links the network support layers and user support layers
a) session layer
b) data link layer
c) transport layer
d) network layer
Answer
Answer: c [Reason:] Physical, data link and network layers are network support layers and session, presentation and application layers are user support layers.
5. Which address is used in an internet employing the TCP/IP protocols?
a) physical address and logical address
b) port address
c) specific address
d) all of the mentioned
Answer
Answer: d [Reason:] None.
6. TCP/IP model was developed _____ the OSI model.
a) prior to
b) after
c) simultaneous to
d) none of the mentioned
Answer
Answer: a [Reason:] None.
7. Which layer is responsible for process to process delivery?
a) network layer
b) transport layer
c) session layer
d) data link layer
Answer
Answer: b [Reason:] None.
8. Which address identifies a process on a host?
a) physical address
b) logical address
c) port address
d) specific address
Answer
Answer: c [Reason:] None.
9. Which layer provides the services to user?
a) application layer
b) session layer
c) presentation layer
d) none of the mentioned
Answer
Answer: a [Reason:] None.
10. Transmission data rate is decided by
a) network layer
b) physical layer
c) data link layer
d) transport layer
Answer
Answer: b [Reason:] None.
