Computer Fundamentals

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.

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. This process is done by proxy server.

WIAS stands for Wide Area Information Server.
This is a program that can index enormous amounts of information and make it searchable across large networks including the Internet. People can search the WAIS index and it will return results by relevance. Searches can then be narrowed down by subsequent searches on the original results. Search engines are a new and improved version of WAIS, specifically for the Web.

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.