Network Administrator Interview Questions And Answers

Network administrator is responsible for the maintenance of computer hardware and software systems that make up a computer network including the maintenance and monitoring of active data network or converged infrastructure and related network equipment.
Network administrators are generally mid-level support staff within an organization and do not typically get involved directly with users. Network administrators focus on network components within a company's LAN/WAN infrastructure ensuring integrity. Depending on the company and its size, the network administrator may also design and deploy networks.

Network management is the operation, administration, maintenance, and provisioning (OAMP) of networked systems. Network management is essential to command and control practices and is generally carried out of a network operations center.

There are 7 OSI reference layers:
☛ Physical Layer
☛ Data Link Layer
☛ Network Layer
☛ Transport Layer
☛ Session Layer
☛ Presentation Layer
☛ Application Layer

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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

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

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.

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

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

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.

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

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.

A hub acts as a multi-port 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.

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

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