Computer Network Questions and Answers

Answer: B

SMTP is used for Email.

The Simple Mail Transfer Protocol carries e-mail from a mail client to its server and between mail servers, usually on port 25 (or 587 for submission). Messages are then read with POP3 or IMAP.

Secure connections are made with TLS or VPNs, files are transferred with FTP, and websites are served with HTTP or HTTPS.

Answer: C

FTP is used for File transfer.

The File Transfer Protocol moves files between a client and a server, using port 21 for commands and a separate connection for the data. It is used, for example, to upload website files to a host.

E-mail uses SMTP, web pages use HTTP or HTTPS, and plain FTP is not even secure, since it sends passwords unencrypted; SFTP or FTPS add security.

Answer: B

VPN stands for Virtual Private Network.

A VPN creates an encrypted tunnel over a public network such as the internet, so that a user can connect securely to a private network, for example an office network from home, as if directly attached to it. It also hides the user's traffic from others on the same network.

'Public', 'Protected' and 'Proxy' are not part of the name; the point of a VPN is to give a private connection over a public network.

Answer: B

The most probable network is a LAN.

A Local Area Network connects computers within a limited area, such as a room, building or campus, usually with Ethernet cables or WiFi. Linking the computers of one administrative block is exactly that.

A MAN (Metropolitan Area Network) covers a city, a WAN (Wide Area Network) spans countries or continents, and a PAN (Personal Area Network) connects one person's devices over a few metres, as with Bluetooth.

Answer: C

The number is the IP address.

An Internet Protocol address is the numerical label assigned to each device connected to a network that uses the internet protocol, such as 192.168.1.10 in IPv4. It identifies the device and lets data be routed to it across the internet.

A MAC address is a hardware identifier of a network interface used within a local network, not for routing across the internet. 'BUS address' and 'BOOT address' are not identifiers of internet-connected devices.

Answer: D

The command that checks IP-level connectivity is Ping.

ping sends ICMP echo request packets to a host and waits for echo replies. A reply shows that the destination is reachable at the IP level and reports the round-trip time; no reply suggests a network or host problem.

The other commands are file-system commands. Deltree deleted a directory together with everything in it in old DOS versions, Dir lists the files in a directory, and Chkdsk checks a disk for file-system errors. None tests a network connection.

Answer: B

The answer is a Virtual Private Network.

A VPN extends a private network across a public network such as the Internet. It creates an encrypted tunnel between the user's device and the private network, so that a remote employee, for example, can use the office network securely as if connected locally.

A Local Area Network covers a small area such as one office or building and does not use public networks. An enterprise private network is an organisation's own network linking its sites, and a storage area network is a dedicated high-speed network connecting servers to storage devices.

Answer: A

Network congestion occurs in case of traffic overloading.

Congestion happens when more data is offered to a network, a link or a router than it can carry. Queues in the routers fill up, packets are delayed or dropped, and throughput falls. Congestion control methods, such as TCP slowing its sending rate, exist to deal with it.

A system terminating, or a connection between two nodes ending, reduces the traffic rather than overloading the network. 'None of the above' is wrong because overloading is the cause.

Answer: A

IPv4 is a 32 bit addressing system.

An IPv4 address is 32 bits long, written as four 8-bit octets in dotted decimal, such as 192.168.1.1. That gives \(2^{32}\), about 4.3 billion, possible addresses, and the shortage of addresses is one reason IPv6 was developed.

128 bit is the length of an IPv6 address. 16 bit is the size of a TCP or UDP port number, and 14 bit is not the length of any standard IP address.

Answer: B

The technology is video conferencing.

Video conferencing links people at two or more locations at the same time by live, two-way audio and video over a network, so that they can see and hear one another. Platforms such as Zoom and Microsoft Teams are everyday examples.

E-mail sends text messages and attachments that are read later, not live audio-video. Animation is the creation of moving images, and e-commerce is buying and selling over the Internet. None of them connects people simultaneously by sound and picture.