The Internet is a global WAN consisting of interconnected networks that use the Internet Protocol Suite (TCP/IP). It is a network of networks that consists of millions of computers, including home, corporation, public, academic, and government computers. The Internet allows users to access a vast array of information resources and services, including web servers that make up the World Wide Web (WWW) and support sending and receiving email. It has also changed the newspaper publishing industry as Web sites, blogging, and web feeds have
grown in popularity and newspaper circulation has declined. Last, streaming media, Voice over Internet Protocol (VoIP), and IPTV have become common.
The World Wide Web (WWW) is a system of interlinked hypertext documents known as web pages that can be viewed with a web browser such as Internet Explorer. Web pages may contain text, images, videos, and other multimedia that you can navigate between by using hyperlinks, and they are usually found by using a search engine such as Bing or Google.
When you view web pages, you are connecting to the web server using TCP port 80. However, the content is not encrypted and could be read by anyone who can access the #data stream. Since personal information can be sent over the Internet, including credit card numbers, a supplemental protocol was developed called SSL. Secure Sockets Layer (SSL) uses TCP port 443, which uses a digital certificate to encrypt the packet so that it cannot be read by anyone else except the source and target. When you are using SSL, the browser URL starts with https (e.g., https://www.acme.com).
Another traditional service provided over the Internet is FTP. File Transfer Protocol (FTP) is a standard network protocol used to transfer a file from one host to another over a TCP/IP-based network. Different from HTTP, it uses two TCP ports to operate—ports 20 and 21.
FTP can be used with user-based password authentication or with anonymous user access.
Unfortunately, the username, password, and data transfers are sent unencrypted. Therefore,
when encryption is needed, you should use SFTP (SSH File Transfer Protocol), or FTPS (FTP over SSL), which adds SSL or TLS encryption.
For emails to travel over the Internet, email servers (or any server or client that sends email
directly out) use Simple Mail Transfer Protocol (SMTP) as an outgoing mail transport. SMTP uses TCP port 25.
Note: Because Web sites using HTML have become common on the Internet and it is readily available on any computer with a browser, this technology is often used within an organization to access internal applications.
This lesson is a part of Popular Windows Network Services and Applications chapter from 98-365 Windows Server Administration Fundamentals Prep course. More lessons in this chapter are
The Practice tests included in this course are: