Data communication

1. Data Communication
Part 11

2. INTERNET
INFORMATION SERVICES (IIS)

3. ◎ IIS enables you to set a maximum connection
limit on your Web server based on available
bandwidth and memory.
◎ This enables you to protect your network against
an overwhelming number of requests due to a
particularly popular page or a type of malicious
attack called a denial of service(DoS) attack.

4. APACHE
◎ UNIX/Linux-based operating systems runApache HTTP
Server.
◎ Apache serves well over 50 percent of the Web sites on
the Internet. Apache is incredibly popular, runs on
multiple operating systems
◎ (including Windows), and, best of all, is free!
◎ Apache is nothing more than an executable program and
a bunch of text files, so it isn’t much to look at.
◎ To ease configuration, most Web administrators use add-
on graphical user interfaces (GUIs) such as Webmin that
make administering Apache a breeze

5. WEBMIN

6. WEB CLIENTS
◎ programs used to surf the Web.
◎ A client program (a Web browser) reads Web
pages supplied by the Web server. r
◎ Web browsers are Microsoft Internet Explorer,
Mozilla Firefox, Apple, Safari, Opera, and Google
Chrome.

7. SECURE SOCKETS LAYER AND
HTTPS
◎ HTTP is not a secure protocol
◎ SSL - Secure Sockets Layer (SSL) .
◎ SSL is a protocol developed by Netscape for transmitting
private documents over the Internet.
◎ SSL works by using a public key to encrypt sensitive data.
This encrypted data is sent over an SSL connection, and
then decrypted at the receiving end using a private
◎ key. All the popular Web browsers and Web servers
support SSL, and many Web sites use the protocol to
obtain confidential user information, such as credit card
numbers.

9. ◎ HTTPS stands for Hypertext Transfer Protocol
over SSL.
◎ HTTPS uses TCP port 443.

10. TELNET
◎ Operating systems didn’t have windows and
pretty icons.
◎ The interface to the mainframe was a command
line
◎ Connect remotely to another computer via the
command line

12. ◎ Telnet is rarely used on the Internet and has
been replaced with Secure Shell (SSH) , a
terminal emulation program that looks exactly
like Telnet but encrypts the data.

13. TELNET SERVERS AND CLIENTS
◎ The oldest Telnet server, found on UNIX and
Linux systems, is the venerable telnetd.
◎ A Telnet client is the computer from which you
log onto the remote
◎ server. Most operating systems have a built-in
Telnet client that you run on a command
prompt.