Computer Networks

Proxy server is used to filter requests. For example, a company might use a proxy server to prevent its employees from accessing a specific set of Web sites. Proxy server sits between a client application, such as a Web browser, and a real server. It intercepts all requests to the real server to see if it can fulfil the requests itself. If not, it forwards the request to the real server. Proxy servers have two main purposes: Improve Performance: A proxy server improves Internet access speeds from a network primarily by using a caching system. Caching saves recently viewed Web sites, images, and files on a local hard drive so that they don't have to be downloaded from the Web again. Filter Requests: Proxy servers can also be used to filter requests. For example, a company might use a proxy server to prevent its employees from accessing a specific set of Web sites. 

192.168.1.1 is a C class IP address. C class IP addresses are from 192.0.0.0 to 223.255.255.255.

Correct answer because only (b) POP and (e) IMAP are email protocols. IMAP (Internet Message Access Protocol) is a method of accessing e-mail messages on a server without having to download them to local hard drive. POP (Post Office Protocol) is standardized method of delivering e-mail messages.(a) TCP, (c) HTTP and (d) IGP are not email protocols because: TCP (Transmission Control Protocol) is one of the main protocols in TCP/IP networks. TCP enables two hosts to establish a connection and exchange streams of data. HTTP (HyperText Transfer Protocol) is the protocol used to transfer data over the World Wide Web. IGP (Integrated Graphics Processor) is a graphics chip that is integrated into a computer's motherboard.

Firewall is used for security in networks. A firewall is a small program that protects your computer and its contents from outsiders on the internet or network. A firewall prevents unauthorised traffic to and from your computer.

Transport layer is responsible to provide the delivery of data for end-to-end hosts.

This layer is responsible for reading and writing data from and onto the file in the OSI model of networking

FTP stands for File Transfer Protocol, which is a standard network protocol used to transfer files from one host to another over a TCP-based network like the internet. 'Translate', 'Transit', and 'Typing' are incorrect terms - FTP specifically deals with transferring files between systems.

It is a firewall that simulates the proper effects of an application so that the application will receive only requests to act properly.

It receives protocol data units, interprets them, and passes through the same or different protocol data units that achieve either the same result or a modified result.

A valid IPv4 address has four octets, each between 0 and 255. Option C (10.10.25.25) satisfies this rule. Options A, B, and D have octets exceeding 255 (256, 257, 258), making them invalid.

POP (Post Office Protocol) is a protocol used by local e-mail clients to retrieve e-mail from a remote server.

LAN (Local Area Network), WAN (Wide Area Network), and MAN (Metropolitan Area Network) are all network classifications based on geographical scope. IPv4 is a network layer protocol that defines IP addressing and packet routing, not a network type. This makes IPv4 the odd one out as it's a protocol standard rather than a network category.

This class is concerned with the protocol of the URL.

EIGRP (Enhanced Interior Gateway Routing Protocol) uses the DUAL (Diffusing Update Algorithm) to calculate loop-free paths and supports unequal cost load balancing across multiple paths. Option A is wrong because RIP uses only hop count. Option B is wrong because OSPF is an open standard. Option D is wrong because BGP is exterior, not interior.