Interview question for Network administrator 5

Q1. What are 10Base2, 10Base5 and 10BaseT Ethernet LANs
10Base2—An Ethernet term meaning a maximum transfer rate of 10 Megabits per second that uses baseband
signaling, with a contiguous cable segment length of 100 meters and a maximum of 2 segments.
10Base5—An Ethernet term meaning a maximum transfer rate of 10 Megabits per second that uses baseband
signaling, with 5 continuous segments not exceeding 100 meters per segment.
10BaseT—An Ethernet term meaning a maximum transfer rate of 10 Megabits per second that uses baseband
signaling and twisted pair cabling.

Q2. What is the difference between an unspecified passive open and a fully specified passive open
An unspecified passive open has the server waiting for a connection request from a client. A fully specified passive open has the server waiting for a connection from a specific client.

Q3. Explain the function of Transmission Control Block
A TCB is a complex data structure that contains a considerable amount of information about each connection.

Q4. What is a Management Information Base (MIB)
A Management Information Base is part of every SNMP-managed device. Each SNMP agent has the MIB database that contains information about the device's status, its performance, connections, and configuration. The MIB is queried by SNMP.

Q5. What is anonymous FTP and why would you use it
Anonymous FTP enables users to connect to a host without using a valid login and password. Usually, anonymous FTP uses a login called anonymous or guest, with the password usually requesting the user's ID for tracking purposes only. Anonymous FTP is used to enable a large number of users to access files on the host without having to go to the trouble of setting up logins for them all. Anonymous FTP systems usually have strict controls over the areas an anonymous user can access.

Q6. What is a pseudo tty
A pseudo tty or false terminal enables external machines to connect through Telnet or rlogin. Without a pseudo tty, no connection can take place.

Q7. Which layer of the 7 layer model provides services to the Application layer over the Session layer connection?
Presentation.

Q8. What does the Mount protocol do ?
The Mount protocol returns a file handle and the name of the file system in which a requested file resides. The message is sent to the client from the server after reception of a client's request.

Q9. What is External Data Representation
External Data Representation is a method of encoding data within an RPC message, used to ensure that the data is not system-dependent.

Q10. Which OSI Reference Layer controls application to application communication?
Session

Q11. BOOTP helps a diskless workstation boot. How does it get a message to the network looking for its IP address and the location of its operating system boot files ?
BOOTP sends a UDP message with a subnetwork broadcast address and waits for a reply from a server that gives it the IP address. The same message might contain the
name of the machine that has the boot files on it. If the boot image location is not specified, the workstation sends another UDP message to query the server.

Q12. What is a DNS resource record
A resource record is an entry in a name server's database. There are several types of resource records used, including name-to-address resolution information. Resource records are maintained as ASCII files.

Q13. What protocol is used by DNS name servers
DNS uses UDP for communication between servers. It is a better choice than TCP because of the improved speed a connectionless protocol offers. Of course, transmission reliability suffers with UDP.

Q14. What is the difference between interior and exterior neighbor gateways
Interior gateways connect LANs of one organization, whereas exterior gateways connect the organization to the outside world.

Q15. What is the HELLO protocol used for
The HELLO protocol uses time instead of distance to determine optimal routing. It is an alternative to the Routing Information Protocol.

Q16. What are the advantages and disadvantages of the three types of routing tables
The three types of routing tables are fixed, dynamic, and fixed central. The fixed table must be manually modified every
time there is a change. A dynamic table changes its information based on network traffic, reducing the amount of manual maintenance. A fixed central table lets a manager
modify only one table, which is then read by other devices. The fixed central table reduces the need to update each machine's table, as with the fixed table. Usually a
dynamic table causes the fewest problems for a network administrator, although the table's contents can change without the administrator being aware of the change
.
Q17. What is a characteristic of Store and Forward switches?
They read the entire frame and check CRC before forwarding.

Q18. What is source route
It is a sequence of IP addresses identifying the route a datagram must follow. A source route may optionally be included in an IP datagram header.

Q19. What is RIP (Routing Information Protocol)
It is a simple protocol used to exchange information between the routers.

Q20. What is SLIP (Serial Line Interface Protocol)
It is a very simple protocol used for transmission of IP datagrams across a serial line.

Q21. What is Proxy ARP
It is using a router to answer ARP requests. This will be done when the originating host believes that a destination is local, when in fact is lies beyond router.

Q22. What is OSPF
It is an Internet routing protocol that scales well, can route traffic along multiple paths, and uses knowledge of an Internet's topology to make accurate routing decisions.

Q23. What is Kerberos
It is an authentication service developed at the Massachusetts Institute of Technology. Kerberos uses encryption to prevent intruders from discovering passwords and gaining unauthorized access to files.

Q24. What is a Multi-homed Host
It is a host that has a multiple network interfaces and that requires multiple IP addresses is called as a Multi-homed Host.

Q25. What is NVT (Network Virtual Terminal)
It is a set of rules defining a very simple virtual terminal interaction. The NVT is used in the start of a Telnet session.

Q26. What is Gateway-to-Gateway protocol
It is a protocol formerly used to exchange routing information between Internet core routers.


Q27. What is BGP (Border Gateway Protocol)
It is a protocol used to advertise the set of networks that can be reached with in an autonomous system. BGP enables this information to be shared with the autonomous system. This is newer than EGP (Exterior Gateway Protocol).

Q28. What is autonomous system
It is a collection of routers under the control of a single administrative authority and that uses a common Interior Gateway Protocol.

Q29. What is EGP (Exterior Gateway Protocol)
It is the protocol the routers in neighboring autonomous systems use to identify the set of networks that can be reached within or via each autonomous system.

Q30. What is IGP (Interior Gateway Protocol)
It is any routing protocol used within an autonomous system.

Q31. What is Mail Gateway
It is a system that performs a protocol translation between different electronic mail delivery protocols.

Q32. What is wide-mouth frog
Wide-mouth frog is the simplest known key distribution center (KDC) authentication protocol.

Q33. What are Digrams and Trigrams
The most common two letter combinations are called as digrams. e.g. th, in, er, re and an. The most common three letter combinations are called as trigrams. e.g. the, ing,
and, and ion.

Q34. What is silly window syndrome
It is a problem that can ruin TCP performance. This problem occurs when data are passed to the sending TCP entity in large blocks, but an interactive application on the
receiving side reads 1 byte at a time.

Q35. What is region
When hierarchical routing is used, the routers are divided into what we call regions, with each router knowing all the details about how to route packets to destinations
within its own region, but knowing nothing about the internal structure of other regions.

Q36. What is multicast routing
Sending a message to a group is called multicasting, and its routing algorithm is called multicast routing.

Q37. What is traffic shaping
One of the main causes of congestion is that traffic is often busy. If hosts could be made to transmit at a uniform rate,congestion would be less common. Another open loop
method to help manage congestion is forcing the packet to be transmitted at a more predictable rate. This is called traffic shaping.

Q38. What is packet filter
Packet filter is a standard router equipped with some extra functionality. The extra functionality allows every incoming or outgoing packet to be inspected. Packets meeting
some criterion are forwarded normally. Those that fail the test are dropped.


Q39. What is virtual path
Along any transmission path from a given source to a given destination, a group of virtual circuits can be grouped together into what is called path.

Q40. What is virtual channel
Virtual channel is normally a connection from one source to one destination, although multicast connections are also permitted. The other name for virtual channel is virtual circuit.

Q41. What is logical link control
One of two sublayers of the data link layer of OSI reference model, as defined by the IEEE 802 standard. This sublayer is responsible for maintaining the link between computers when they are sending data across the physical network connection.

Q42. Why should you care about the OSI Reference Model
It provides a framework for discussing network operations and design.

Q43. What is the difference between routable and non- routable protocols
Routable protocols can work with a router and can be used to build large networks. Non-Routable protocols are designed to work on small, local networks and cannot be used with a router.

Q44. What is MAU
In token Ring , hub is called Multistation Access Unit(MAU).

Q45. Explain 5-4-3 rule
In a Ethernet network, between any two points on the network, there can be no more than five network segments or four repeaters, and of those five segments only three of
segments can be populated.

Q46. What is the difference between TFTP and FTP application layer protocols
The Trivial File Transfer Protocol (TFTP) allows a local host to obtain files from a remote host but does not provide reliability or security. It uses the fundamental packet delivery services offered by UDP. The File Transfer Protocol (FTP) is the standard mechanism provided by TCP / IP for copying a file from one host to another. It uses the services offered by TCP and so is
reliable and secure. It establishes two connections (virtual circuits) between the hosts, one for data transfer and another for control information.

Q47. What is the range of addresses in the classes of internet addresses
Class A 0.0.0.0 - 127.255.255.255
Class B 128.0.0.0 - 191.255.255.255
Class C 192.0.0.0 - 223.255.255.255
Class D 224.0.0.0 - 239.255.255.255
Class E 240.0.0.0 - 247.255.255.255

Q48. What is the minimum and maximum length of the header in the TCP segment and IP datagram
The header should have a minimum length of 20 bytes and can have a maximum length of 60 bytes.

49. What is difference between ARP and RARP
The address resolution protocol (ARP) is used to associate the 32 bit IP address with the 48 bit physical address, used by a host or a router to find the physical address of
another host on its network by sending a ARP query packet that includes the IP address of the receiver. The reverse address resolution protocol (RARP) allows a host to discover its Internet address when it knows only its physical address.

Q50. What is ICMP
ICMP is Internet Control Message Protocol, a network layer protocol of the TCP/IP suite used by hosts and gateways to send notification of datagram problems back to the sender. It uses the echo test / reply to test whether a destination is reachable and responding. It also handles both control and error messages.

Q51. What are the data units at different layers of the TCP / IP protocol suite
The data unit created at the application layer is called a message, at the transport layer the data unit created is called either a segment or an user datagram, at the network layer the data unit created is called the datagram, at the data link layer the datagram is encapsulated in to a frame and finally transmitted as signals along the transmission media.

Q52. What is Project 802
It is a project started by IEEE to set standards that enable intercommunication between equipment from a variety of
manufacturers. It is a way for specifying functions of the physical layer, the data link layer and to some extent the network layer to allow for interconnectivity of major LAN
protocols.
It consists of the following:
802.1 is an internetworking standard for compatibility of different LANs and MANs across protocols.
802.2 Logical link control (LLC) is the upper sublayer of the data link layer which is non-architecture-specific, that is
remains the same for all IEEE-defined LANs.
Media access control (MAC) is the lower sublayer of the data link layer that contains some distinct modules each
carrying proprietary information specific to the LAN product
being used. The modules are Ethernet LAN (802.3), Token ring LAN (802.4), Token bus LAN (802.5).
802.6 is distributed queue dual bus (DQDB) designed to be used in MANs.

Q53. What is Bandwidth
Every line has an upper limit and a lower limit on the frequency of signals it can carry. This limited range is called the
bandwidth.

Q54. Difference between bit rate and baud rate.
Bit rate is the number of bits transmitted during one second whereas baud rate refers to the number of signal units per
second that are required to represent those bits.
baud rate = bit rate / N where N is no-of-bits represented by each signal shift.

Q55. What is MAC address
The address for a device as it is identified at the Media Access Control (MAC) layer in the network architecture. MAC
address is usually stored in ROM on the network adapter card and is unique.

Q56. What is attenuation
The degeneration of a signal over distance on a network cable is called attenuation.

Q57. What is cladding
A layer of a glass surrounding the center fiber of glass inside a fiber-optic cable.

Q58. What is RAID
A method for providing fault tolerance by using multiple hard disk drives.

Q59. What is NETBIOS and NETBEUI
NETBIOS is a programming interface that allows I/O requests to be sent to and received from a remote computer and it
hides the networking hardware from applications.
NETBEUI is NetBIOS extended user interface. A transport protocol designed by microsoft and IBM for the use on small
subnets.

Q60. What is redirector
Redirector is software that intercepts file or prints I/O requests and translates them into network requests. This comes under presentation layer.

Q61. What is Beaconing
The process that allows a network to self-repair networks problems. The stations on the network notify the other stations on the ring when they are not receiving the transmissions. Beaconing is used in Token ring and FDDI networks.

Q62. What is terminal emulation, in which layer it comes
Telnet is also called as terminal emulation. It belongs to application layer.

Q63. What is frame relay, in which layer it comes
Frame relay is a packet switching technology. It will operate in the data link layer.

Q64. What do you meant by "triple X" in Networks
The function of PAD (Packet Assembler Disassembler) is described in a document known as X.3. The standard protocol has been defined between the terminal and the PAD, called X.28; another standard protocol exists between hte PAD and the network, called X.29. Together, these three recommendations are often called "triple X"

Q65. What is SAP
Series of interface points that allow other computers to communicate with the other layers of network protocol stack.

Q66. What is subnet
A generic term for section of a large networks usually separated by a bridge or router.

Q67. What is Brouter
Hybrid devices that combine the features of both bridges and routers.

Q68. How Gateway is different from Routers
A gateway operates at the upper levels of the OSI model and translates information between two completely different network architectures or data formats.

Q69. What are the different type of networking / internetworking devices
Repeater:
Also called a regenerator, it is an electronic device that operates only at physical layer. It receives the signal in the
network before it becomes weak, regenerates the original bit pattern and puts the refreshed copy back in to the link.

Bridges:
These operate both in the physical and data link layers of LANs of same type. They divide a larger network in to smaller
segments. They contain logic that allow them to keep the traffic for each segment separate and thus are repeaters that relay a frame only the side of the segment containing the intended recipent and control congestion.

Routers:
They relay packets among multiple interconnected networks (i.e. LANs of different type). They operate in the physical,
data link and network layers. They contain software that enable them to determine which of the several possible paths is the best for a particular transmission.

Gateways:
They relay packets among networks that have different protocols (e.g. between a LAN and a WAN). They accept a
packet formatted for one protocol and convert it to a packet formatted for another protocol before forwarding it. They operate in all seven layers of the OSI model.

Q70. What is mesh network
A network in which there are multiple network links between computers to provide multiple paths for data to travel.

Q71. What is passive topology
When the computers on the network simply listen and receive the signal, they are referred to as passive because they don’t amplify the signal in any way. Example for passive topology - linear bus.

Q72. What are the important topologies for networks

BUS topology:
In this each computer is directly connected to primary network cable in a single line.
Advantages:
Inexpensive, easy to install, simple to understand, easy to extend.

STAR topology:
In this all computers are connected using a central hub.
Advantages:
Can be inexpensive, easy to install and reconfigure and easy to trouble shoot physical problems.

RING topology:
In this all computers are connected in loop.
Advantages:
All computers have equal access to network media, installation can be simple, and signal does not degrade as much as
in other topologies because each computer regenerates it.

Q73. What are major types of networks and explain
Server-based network
Peer-to-peer network
Peer-to-peer network, computers can act as both servers sharing resources and as clients using the resources.
Server-based networks provide centralized control of network resources and rely on server computers to provide
security and network administration

Q74. What is Protocol Data Unit
The data unit in the LLC level is called the protocol data unit (PDU). The PDU contains of four fields a destination
service access point (DSAP), a source service access point (SSAP), a control field and an information field. DSAP, SSAP are addresses used by the LLC to identify the protocol stacks on the receiving and sending machines that are generating and using the data. The control field specifies whether the PDU frame is a information frame (I -
frame) or a supervisory frame (S - frame) or a unnumbered frame (U - frame).

Q75. What is difference between baseband and broadband transmission
In a baseband transmission, the entire bandwidth of the cable is consumed by a single signal. In broadband transmission, signals are sent on multiple frequencies, allowing multiple signals to be sent simultaneously.

Q76. What are the possible ways of data exchange
(i) Simplex (ii) Half-duplex (iii) Full-duplex.

Q77. What are the types of Transmission media
Signals are usually transmitted over some transmission media that are broadly classified in to two categories.
Guided Media:
These are those that provide a conduit from one device to another that include twisted-pair, coaxial cable and fiber-optic
cable. A signal traveling along any of these media is directed and is contained by the physical limits of the medium. Twisted-pair and coaxial cable use metallic that accept and transport signals in the form of electrical current. Optical fiber is a glass or plastic cable that accepts and transports signals in the form of light.
Unguided Media:
This is the wireless media that transport electromagnetic waves without using a physical conductor. Signals are
broadcast either through air. This is done through radio
communication, satellite communication and cellular telephony.



Q78. Difference between the communication and transmission.
Transmission is a physical movement of information and concern issues like bit polarity, synchronization, clock etc.
Communication means the meaning full exchange of information between two communication media.

Q79.The Internet Control Message Protocol occurs at what layer of the seven layer model?
Network

Q80.Which protocol resolves an IP address to a MAC address?
ARP

Q81.MIDI and MPEG are examples of what layer of the OSI seven layer model?
Presentation

Q82.What is the protocol number for UDP?
17

Q83.Which protocol is used for booting diskless workstations?
RARP

Q84.Which layer is responsible for putting 1s and 0s into a logical group?
Physical

Q85.What does 'P' mean when running a Trace?
Protocol unreachable

Q86.UDP works at which layer of the DOD model?
Host to Host

Q87.What is the default encapsulation of Netware 3.12?
802.2

Q88.Ping uses which Internet layer protocol?
ICMP

Q89.Which switching technology can reduce the size of a broadcast domain?
VLAN

Q90.What is the first step in data encapsulation? 
User information is converted into data.

Q91.What is the protocol number for TCP?
6

Q92.What do you use the Aux port for?
Modem

Q93.Repeaters work at which layer of the OSI model?
Physical

Q94.WAN stands for which of the following?
Wide Area Network

Q95.What ISDN protocol specifies concepts, terminology, and services?
I

Q96.LAN stands for which of the following?
Local Are Network

Q97.DHCP stands for 
Dynamic Host Configuration Protocol

Q98.What does the acronym ARP stand for?
Address Resolution Protocol

Q99.Which layer is responsible for identifying and establishing the availability of the intended communication partner?
Application.

Q100.Which OSI layer provides mechanical, electrical, procedural for activating, maintaining physical link?
Physical.

Interview question for Network administrator 4

Interview Questions for Network Administrator and Support Staff

I suggest you group your questions by general topic: reporting and organization, architecture and hardware, policies and user requirements, backup and security, and so on… Make up your own categories.

• What is your role as a Network Administrator as part of [company name]’s Information Technology department? Please describe your job responsibilities.
• Who do you report to? Who reports to you?
• Do you have an organizational chart that shows the relationship of people in your organization?
• Who does strategic planning for information systems in your company? Is there a committee to support this activity?
• What are some major network securities issues Network Administrators face on job daily?
• What are the most common networking problems that you as a Network Administrator deal with on a daily basis?
• What are some of the more common user problems that Network Technicians face on a daily basis?
• Does [company name] have a WAN infrastructure?
• Does [company name] have an operating Intranet? What is the Intranet for?
• Do you feel [company name]’s basic LAN infrastructure is secure from outside attacks?
• What type of network topology does [company name] currently use (i.e. token ring, star, bus, etc.)? What hardware standards are in use for the network?
• Does [company name]’s network have one main server or multiple servers for data backup? What kind of backup or redundancy is used to protect data?
• What type of OS are you running on workstations and your desktop currently? Is there a company standard for Operating Systems and/or other software?
• What transmission medium does [company name] use for its network?
• How old is the company’s infrastructure?
• How many users does this network support? Are all workstations in the immediate area?
• If all workstations and company servers are not in one location, what technologies are used for WAN connectivity?
• How many gateways, proxy servers, web servers, and mail servers does [company name] have?
• What protocols and standards does [company name] demand for its network?
• How is often does [company name] perform backups and restoration of data?
• How often is security auditing performed?
• What actions are taken for Load Balancing?
• What is [company name]’s current security policy?
• Does [company name] have a security response policy?
• Does [company name] allow for the use of remote access for telecommuters?
• Does [company name] employ a public key encryption?

Interview question for Network administrator 3

1) What is a Link?

A link refers to the connectivity between two devices. It includes the type of cables and protocols used in order for one device to be able to communicate with the other.

2) What are the layers of the OSI reference model?

There are 7 OSI layers: Physical Layer, Data Link Layer, Network Layer, Transport Layer, Session Layer, Presentation Layer and Application Layer.

3) What is backbone network?

A backbone network is a centralized infrastructure that is designed to distribute different routes and data to various networks. It also handles management of bandwidth and various channels.

4) What is a LAN?

LAN is short for Local Area Network. It refers to the connection between computers and other network devices that are located within a small physical location.

5) What is a node?

A node refers to a point or joint where a connection takes place. It can be computer or device that is part of a network. Two or more nodes are needed in order to form a network connection.

6) What are routers?

Routers can connect two or more network segments. These are intelligent network devices that store information in its routing table such as paths, hops and bottlenecks. With this info, they are able to determine the best path for data transfer. Routers operate at the OSI Network Layer.

7) What is point to point link?

It refers to a direct connection between two computers on a network. A point to point connection does not need any other network devices other than connecting a cable to the NIC cards of both computers.

8) What is anonymous FTP?

Anonymous FTP is a way of granting user access to files in public servers. Users that are allowed access to data in these servers do not need to identify themselves, but instead log in as an anonymous guest.

9) What is subnet mask?

A subnet mask is combined with an IP address in order to identify two parts: the extended network address and the host address. Like an IP address, a subnet mask is made up of 32 bits.

10) What is the maximum length allowed for a UTP cable?

A single segment of UTP cable has an allowable length of 90 to 100 meters. This limitation can be overcome by using repeaters and switches.

11) What is data encapsulation?

Data encapsulation is the process of breaking down information into smaller manageable chunks before it is transmitted across the network. It is also in this process that the source and destination addresses are attached into the headers, along with parity checks.

12) Describe Network Topology

Network Topology refers to the layout of a computer network. It shows how devices and cables are physically laid out, as well as how they connect to one another.

13) What is VPN?

VPN means Virtual Private Network, a technology that allows a secure tunnel to be created across a network such as the Internet. For example, VPNs allow you to establish a secure dial-up connection to a remote server.

14) Briefly describe NAT.

NAT is Network Address Translation. This is a protocol that provides a way for multiple computers on a common network to share single connection to the Internet.

15) What is the job of the Network Layer under the OSI reference model?

The Network layer is responsible for data routing, packet switching and control of network congestion. Routers operate under this layer.

16) How does a network topology affect your decision in setting up a network?

Network topology dictates what media you must use to interconnect devices. It also serves as basis on what materials, connector and terminations that is applicable for the setup.

17) What is RIP?

RIP, short for Routing Information Protocol is used by routers to send data from one network to another. It efficiently manages routing data by broadcasting its routing table to all other routers within the network. It determines the network distance in units of hops.

18) What are different ways of securing a computer network?

There are several ways to do this. Install reliable and updated anti-virus program on all computers. Make sure firewalls are setup and configured properly. User authentication will also help a lot. All of these combined would make a highly secured network.

19) What is NIC?

NIC is short for Network Interface Card. This is a peripheral card that is attached to a PC in order to connect to a network. Every NIC has its own MAC address that identifies the PC on the network.

20) What is WAN?

WAN stands for Wide Area Network. It is an interconnection of computers and devices that are geographically dispersed. It connects networks that are located in different regions and countries.

21) What is the importance of the OSI Physical Layer?

The physical layer does the conversion from data bits to electrical signal, and vice versa. This is where network devices and cable types are considered and setup.

22) How many layers are there under TCP/IP?

There are four layers: the Network Layer, Internet Layer, Transport Layer and Application Layer.

23) What are proxy servers and how do they protect computer networks?

Proxy servers primarily prevent external users who identifying the IP addresses of an internal network. Without knowledge of the correct IP address, even the physical location of the network cannot be identified. Proxy servers can make a network virtually invisible to external users.

24) What is the function of the OSI Session Layer?

This layer provides the protocols and means for two devices on the network to communicate with each other by holding a session.  This includes setting up the session, managing information exchange during the session, and tear-down process upon termination of the session.

25) What is the importance of implementing a Fault Tolerance System? Are there limitations?

A fault tolerance system ensures continuous data availability. This is done by eliminating a single point of failure. However, this type of system would not be able to protect data in some cases, such as in accidental deletions.

26) What does 10Base-T mean?

The 10 refers to the data transfer rate, in this case is 10Mbps. The word Base refers to base band, as oppose to broad band. T means twisted pair, which is the cable used for that network.

27) What is a private IP address?

Private IP addresses are assigned for use on intranets. These addresses are used for internal networks and are not routable on external public networks. These ensures that no conflicts are present among internal networks while at the same time the same range of private IP addresses are reusable for multiple intranets since they do not “see” each other.

28) What is NOS?

NOS, or Network Operating System, is specialized software whose main task is to provide network connectivity to a computer in order for it to be able to communicate with other computers and connected devices.

29) What is DoS?

DoS, or Denial-of-Service attack, is an attempt to prevent users from being able to access the internet or any other network services. Such attacks may come in different forms and are done by a group of perpetuators. One common method of doing this is to overload the system server so it cannot anymore process legitimate traffic and will be forced to reset.

30) What is OSI and what role does it play in computer networks?

OSI (Open Systems Interconnect) serves as a reference model for data communication. It is made up of 7 layers, with each layer defining a particular aspect on how network devices connect and communicate with one another. One layer may deal with the physical media used, while another layer dictates how data is actually transmitted across the network.

31) What is the purpose of cables being shielded and having twisted pairs?

The main purpose of this is to prevent crosstalk. Crosstalks are electromagnetic interferences or noise that can affect data being transmitted across cables.

32) What is the advantage of address sharing?

By using address translation instead of routing, address sharing provides an inherent security benefit. That’s because host PCs on the Internet can only see the public IP address of the external interface on the computer that provides address translation and not the private IP addresses on the internal network.

33) What are MAC addresses?

MAC, or Media Access Control, uniquely identifies a device on the network. It is also known as physical address or Ethernet address. A MAC address is made up of 6-byte parts.

34) What is the equivalent layer or layers of the TCP/IP Application layer in terms of OSI reference model?

The TCP/IP Application layer actually has three counterparts on the OSI model: the Session layer, Presentation Layer and Application Layer.

35) How can you identify the IP class of a given IP address?

By looking at the first octet of any given IP address, you can identify whether it’s Class A, B or C. If the first octet begins with a 0 bit, that address is Class A. If it begins with bits 10 then that address is a Class B address. If it begins with 110, then it’s a Class C network.

36) What is the main purpose of OSPF?

OSPF, or Open Shortest Path First, is a link-state routing protocol that uses routing tables to determine the best possible path for data exchange.

37) What are firewalls?

Firewalls serve to protect an internal network from external attacks. These external threats can be hackers who want to steal data or computer viruses that can wipe out data in an instant. It also prevents other users from external networks from gaining access to the private network.

38) Describe star topology

Star topology consists of a central hub that connects to nodes. This is one of the easiest to setup and maintain.

39) What are gateways?

Gateways provide connectivity between two or more network segments. It is usually a computer that runs the gateway software and provides translation services. This translation is a key in allowing different systems to communicate on the network.

40) What is the disadvantage of a star topology?

One major disadvantage of star topology is that once the central hub or switch get damaged, the entire network becomes unusable.

41) What is SLIP?

SLIP, or Serial Line Interface Protocol, is actually an old protocol developed during the early UNIX days. This is one of the protocols that are used for remote access.

42) Give some examples of private network addresses.

10.0.0.0 with a subnet mask of 255.0.0.0
172.16.0.0 with subnet mask of 255.240.0.0
192.168.0.0 with subnet mask of 255.255.0.0

43) What is tracert?

Tracert is a Windows utility program that can used to trace the route taken by data from the router to the destination network. It also shows the number of hops taken during the entire transmission route.

44) What are the functions of a network administrator?

A network administrator has many responsibilities that can be summarize into 3 key functions: installation of a network, configuration of network settings, and maintenance/troubleshooting of networks.

45) Describe at one disadvantage of a peer to peer network.

When you are accessing the resources that are shared by one of the workstations on the network, that workstation takes a performance hit.

46) What is Hybrid Network?

A hybrid network is a network setup that makes use of both client-server and peer-to-peer architecture.

47) What is DHCP?

DHCP is short for Dynamic Host Configuration Protocol. Its main task is to automatically assign an IP address to devices across the network. It first checks for the next available address not yet taken by any device, then assigns this to a network device.

48) What is the main job of the ARP?

The main task of ARP or Address Resolution Protocol is to map a known IP address to a MAC layer address.

49) What is TCP/IP?

TCP/IP is short for Transmission Control Protocol / Internet Protocol. This is a set of protocol layers that is designed to make data exchange possible on different types of computer networks, also known as heterogeneous network.

50) How can you manage a network using a router?

Routers have built in console that lets you configure different settings, like security and data logging. You can assign restrictions to computers, such as what resources it is allowed access, or what particular time of the day they can browse the internet. You can even put restrictions on what websites are not viewable across the entire network.

51) What protocol can be applied when you want to transfer files between different platforms, such between UNIX systems and Windows servers?

Use FTP (File Transfer Protocol) for file transfers between such different servers. This is possible because FTP is platform independent.

52) What is the use of a default gateway?

Default gateways provide means for the local networks to connect to the external network. The default gateway for connecting to the external network is usually the address of the external router port.

53) One way of securing a network is through the use of passwords. What can be considered as good passwords?

Good passwords are made up of not just letters, but by combining letters and numbers. A password that combines uppercase and lowercase letters is favorable than one that uses all upper case or all lower case letters. Passwords must be not words that can easily be guessed by hackers, such as dates, names, favorites, etc. Longer passwords are also better than short ones.

54) What is the proper termination rate for UTP cables?

The proper termination for unshielded twisted pair network cable is 100 ohms.

55) What is netstat?

Netstat is a command line utility program. It provides useful information about the current TCP/IP settings of a connection.

56) What is the number of network IDs in a Class C network?

For a Class C network, the number of usable Network ID bits is 21. The number of possible network IDs is 2 raised to 21 or 2,097,152. The number of host IDs per network ID is 2 raised to 8 minus 2, or 254.

57) What happens when you use cables longer than the prescribed length?

Cables that are too long would result in signal loss. This means that data transmission and reception would be affected, because the signal degrades over length.

58) What common software problems can lead to network defects?

Software related problems can be any or a combination of the following:
– client server problems
– application conflicts
– error in configuration
– protocol mismatch
– security issues
– user policy and rights issues

59) What is ICMP?

ICMP is Internet Control Message Protocol. It provides messaging and communication for protocols within the TCP/IP stack. This is also the protocol that manages error messages that are used by network tools such as PING.

60) What is Ping?

Ping is a utility program that allows you to check connectivity between network devices on the network. You can ping a device by using its IP address or device name, such as a computer name.

61) What is peer to peer?

Peer to peer are networks that does not reply on a server. All PCs on this network act as individual workstations.

62) What is DNS?

DNS is Domain Name System. The main function of this network service is to provide host names to TCP/IP address resolution.

63) What advantages does fiber optics have over other media?

One major advantage of fiber optics is that is it less susceptible to electrical interference. It also supports higher bandwidth, meaning more data can be transmitted and received. Signal degrading is also very minimal over long distances.

64) What is the difference between a hub and a switch?

A hub acts as a multiport repeater. However, as more and more devices connect to it, it would not be able to efficiently manage the volume of traffic that passes through it. A switch provides a better alternative that can improve the performance especially when high traffic volume is expected across all ports.

65) What are the different network protocols that are supported by Windows RRAS services?

There are three main network protocols supported: NetBEUI, TCP/IP, and IPX.

66) What are the maximum networks and hosts in a class A, B and C network?

For Class A, there are 126 possible networks and 16,777,214 hosts
For Class B, there are 16,384 possible networks and 65,534 hosts
For Class C, there are 2,097,152 possible networks and 254 hosts

67) What is the standard color sequence of a straight-through cable?

orange/white, orange, green/white, blue, blue/white, green, brown/white, brown.

68) What protocols fall under the Application layer of the TCP/IP stack?

The following are the protocols under TCP/IP Application layer: FTP, TFTP, Telnet and SMTP.

69) You need to connect two computers for file sharing. Is it possible to do this without using a hub or router?

Yes, you can connect two computers together using only one cable. A crossover type cable can be use in this scenario. In this setup, the data transmit pin of one cable is connected to the data receive pin of the other cable, and vice versa.

70) What is ipconfig?

Ipconfig is a utility program that is commonly used to identify the addresses information of a computer on a network. It can show the physical address as well as the IP address.

71) What is the difference between a straight-through and crossover cable?

A straight-through cable is used to connect computers to a switch, hub or router. A crossover cable is used to connect two similar devices together, such as a PC to PC or Hub to hub.

72) What is client/server?

Client/server is a type of network wherein one or more computers act as servers. Servers provide a centralized repository of resources such as printers and files. Clients refers to workstation that access the server.

73) Describe networking.

Networking refers to the inter connection between computers and peripherals for data communication. Networking can be done using wired cabling or through wireless link.

74) When you move the NIC cards from one PC to another PC, does the MAC address gets transferred as well?

Yes, that’s because MAC addresses are hard-wired into the NIC circuitry, not the PC. This also means that a PC can have a different MAC address when the NIC card was replace by another one.

75) Explain clustering support

Clustering support refers to the ability of a network operating system to connect multiple servers in a fault-tolerant group. The main purpose of this is the in the event that one server fails, all processing will continue on with the next server in the cluster.

76) In a network that contains two servers and twenty workstations, where is the best place to install an Anti-virus program?

An anti-virus program must be installed on all servers and workstations to ensure protection. That’s because individual users can access any workstation and introduce a computer virus when plugging in their removable hard drives or flash drives.

77) Describe Ethernet.

Ethernet is one of the popular networking technologies used these days. It was developed during the early 1970s and is based on specifications as stated in the IEEE. Ethernet is used in local area networks.

78) What are some drawbacks of implementing a ring topology?

In case one workstation on the network suffers a malfunction, it can bring down the entire network. Another drawback is that when there are adjustments and reconfigurations needed to be performed on a particular part of the network, the entire network has to be temporarily brought down as well.

79) What is the difference between CSMA/CD and CSMA/CA?

CSMA/CD, or Collision Detect, retransmits data frames whenever a collision occurred. CSMA/CA, or Collision Avoidance, will first broadcast intent to send prior to data transmission.

80) What is SMTP?

SMTP is short for Simple Mail Transfer Protocol. This protocol deals with all Internal mail, and provides the necessary mail delivery services on the TCP/IP protocol stack.

81) What is multicast routing?

Multicast routing is a targeted form of broadcasting that sends message to a selected group of user, instead of sending it to all users on a subnet.

82) What is the importance of Encryption on a network?

Encryption is the process of translating information into a code that is unreadable by the user. It is then translated back or decrypted back to its normal readable format using a secret key or password. Encryption help ensure that information that is intercepted halfway would remain unreadable because the user has to have the correct password or key for it.

83) How are IP addresses arranged and displayed?

IP addresses are displayed as a series of four decimal numbers that are separated by period or dots. Another term for this arrangement is the dotted decimal format. An example is 192.168.101.2

84) Explain the importance of authentication.

Authentication is the process of verifying a user’s credentials before he can log into the network. It is normally performed using a username and password. This provides a secure means of limiting the access from unwanted intruders on the network.

85) What do mean by tunnel mode?

This is a mode of data exchange wherein two communicating computers do not use IPSec themselves. Instead, the gateway that is connecting their LANs to the transit network creates a virtual tunnel that uses the IPSec protocol to secure all communication that passes through it.

86) What are the different technologies involved in establishing WAN links?

Analog connections – using conventional telephone lines; Digital connections – using digital-grade telephone lines; switched connections – using multiple sets of links between sender and receiver to move data.

87) What is one advantage of mesh topology?

In the event that one link fails, there will always be another available. Mesh topology is actually one of the most fault-tolerant network topology.

88) When troubleshooting computer network problems, what common hardware-related problems can occur?

A large percentage of a network is made up of hardware. Problems in these areas can range from malfunctioning hard drives, broken NICs and even hardware startups. Incorrectly hardware configuration is also one of those culprits to look into.

89) What can be done to fix signal attenuation problems?

A common way of dealing with such a problem is to use repeaters and hub, because it will help regenerate the signal and therefore prevent signal loss. Checking if cables are properly terminated is also a must.

90) How does dynamic host configuration protocol aid in network administration?

Instead of having to visit each client computer to configure a static IP address, the network administrator can apply dynamic host configuration protocol to create a pool of IP addresses known as scopes that can be dynamically assigned to clients.

91) Explain profile in terms of networking concept?

Profiles are the configuration settings made for each user. A profile may be created that puts a user in a group, for example.

92) What is sneakernet?

Sneakernet is believed to be the earliest form of networking wherein data is physically transported using removable media, such as disk, tapes.

93) What is the role of IEEE in computer networking?

IEEE, or the Institute of Electrical and Electronics Engineers, is an organization composed of engineers that issues and manages standards for electrical and electronic devices. This includes networking devices, network interfaces, cablings and connectors.

94) What protocols fall under the TCP/IP Internet Layer?

There are 4 protocols that are being managed by this layer. These are ICMP, IGMP, IP and ARP.

95) When it comes to networking, what are rights?

Rights refer to the authorized permission to perform specific actions on the network. Each user on the network can be assigned individual rights, depending on what must be allowed for that user.

96) What is one basic requirement for establishing VLANs?

A VLAN requires dedicated equipment on each end of the connection that allows messages entering the Internet to be encrypted, as well as for authenticating users.

97) What is IPv6?

IPv6 , or Internet Protocol version 6, was developed to replace IPv4. At present, IPv4 is being used to control internet traffic, butis expected to get saturated in the near future. IPv6 was designed to overcome this limitation.

98) What is RSA algorithm?

RSA is short for Rivest-Shamir-Adleman algorithm. It is the most commonly used public key encryption algorithm in use today.

99) What is mesh topology?

Mesh topology is a setup wherein each device is connected directly to every other device on the network. Consequently, it requires that each device have at least two network connections.

100) what is the maximum segment length of a 100Base-FX network?

The maximum allowable length for a network segment using 100Base-FX is 412 meters. The maximum length for the entire network is 5 kilometers.