Transcript Slide 1

Web Servers
• Web server software is a product that works with
the operating system
• The server computer can run more than one
software product such as e-mail and FTP
• With both a LAN and the Web, controlling
access is very important
• The Web server can be part of the LAN
• Web communication and LAN communication
are different
Web Server PlatformsMicrosoft
• Windows NT (IIS 4)
– IIS (Internet Information Server) was added in the
mid-1990s, and support for ASP was added later
• Windows 2000 (IIS 5)
– IIS part of the OS from the beginning
– .NET Framework add-on allows use of ASP.NET
• Windows Server 2003 (IIS 6)
– .NET Framework integrated into OS
Other Microsoft Server Products
• Application Center
– Allows you to manage a cluster of servers as
if it is one server
• Biztalk Server
– Connects to your business partners using
• Commerce Server
– Builds e-commerce sites in a short amount of
Other Microsoft Server Products
• Internet Security and Acceleration Server
– Combines a firewall product with a Web cache
• Operations Manager
– Helps decrease support costs for a server
• SharePoint Portal Server
– Set up a site that is highly personalized
Configuring TCP/IP in Windows
• To determine TCP/IP configuration, type
ipconfig at a command prompt
How a Web Server Works
• HTTP (Hypertext Transfer Protocol) defines how
information is passed between a browser and a
Web server
• The two most popular Web servers are
– Apache from Apache Software Foundation
– Internet Information Services (IIS) from Microsoft
• The original Web server from Microsoft available on Windows
NT was Internet Information Server
• Almost two-thirds of all Web servers use Apache
How a Web Server Works
• As is true with other servers such as DNS,
Web servers listen for communication at a
– The default port is 80
– You can also create Web servers at port
numbers greater than 1023
• Each Web server has a root, which is
where you store the HTML documents
Understanding HTTP
• The current version of HTTP is 1.1
– Virtually no browsers are so old that they do
not support 1.1
• HTTP is a stateless protocol, meaning that
each Web page sent is independent of
every other Web page sent
– This makes it more challenging to create a
shopping cart application
Understanding HTTP
• HTTP 1.1 supports persistent connections
– This allows the browser to receive multiple
files in one TCP connection
– This can speed up communication
– Although you see a single page in your
browser, it can be composed of many text and
image files
Understanding HTTP
• When the browser sends a request to a Web
server, it looks like:
GET /hello.htm HTTP/1.1
• The above requests the hello.htm file from the
root of the Web server
• It specifies the host of
– There could be multiple hosts at the IP address
Understanding HTTP
• The following shows some of the headers
along with the HTML that the Web server
would send:
HTTP/1.1 200 OK
Server: Microsoft-IIS/5.0
Content-Type: text/html
Last-Modified: Fri, 17 May 2005 18:21:25 GMT
Content-Length: 43
Hello, World
• The headers contain information about the
Features in Apache
• Apache 1.3 was used for many years but version 2.0
was released in 2001
• Apache can also be used as a proxy server
– A proxy server isolates your real Web server from the
• Apache 2.0 has
Better support for Windows
Support for IPv6
Simplified configuration
Unicode support in Windows
Multilanguage error responses
• Apache supports many programming languages such
as Perl and PHP
Features in IIS
• IIS versions associated with Windows
– Windows NT – IIS 4.0
– Windows 2000 – IIS 5.0
– Windows Server 2003 – IIS 6.0
• SMTP can be easily added so you can
send e-mail from your Web pages
Features in IIS 5.0
• Web Distributed Authoring and Versioning
– Allows a server to share Web-based files
• Named virtual hosting
– Multiple Web sites can share a single IP address
• Per Web site bandwidth throttling
– Control bandwidth by Web site
• Kerberos authentication
• Secure Sockets Layer 3.0
– Encrypted communication
Features in IIS 6.0
• Increased security
– Default permits only HTML documents
• Expanded language support
– Can use XML and SOAP
• Support for IPv6
• Increased dependability
– Kernel-mode HTTP service
– Self-healing mechanism
Components in IIS
• File Transfer Protocol (FTP) server
– To transfer files between user and server
• FrontPage 2000 Server Extensions
– Used by programs to transfer files to and from a Web
• NNTP Service
– Used to create user forums
• SMTP Service
• World Wide Web Server
File System Permissions
• Permission allow you to control access
to the resources on a computer such as
a Web page, a document, or a program
• In Windows, the NTFS file system is
required in order to assign permissions
• All Linux file systems incorporate
File System Permissions in
Full Control
Full Control includes all other permissions and allows you to take
ownership of the file or folder and change the attributes of a file
Allows read, write, and delete
With this permission, you can read files but cannot execute them
When set on a file, this permission allows you to write to files; when
set on a folder, you can write to the folder
Read & Execute
Read files and run programs
List Folder Contents
This permission allows you to view the contents of a folder
Special Permissions
(Windows 2003
This is not a specific permission; under the list of permissions for
users, when this permission is checked, it means that this user
has one or more of the 14 individual permissions set
Hosting Multiple Web Sites
by Port Number
• Associate each new Web site with a
port above 1023
• To retrieve a Web page from a site at
port 8080
• Because it requires a user to add the
port number, it is not a popular method
• UNIX was introduced in 1969
• Linux is from the early 1990s
– Based on MINIX
• Three basic components
– Kernel – central portion of OS
– File system – provides input and output
– Shell – provides user interface
• Source code is freely available
– Developers can make changes
• Available from a number of organizations
– Red Hat
– Mandrake
– SuSe
• Server administration focuses on LANs
• Web server administration focuses on the
• Both types of administrators install,
configure, and maintain servers
• Many pieces make up the network
• There are many Web server platforms
from which to choose
• Web servers use HTTP to send HTML
• IIS is from Microsoft while Apache is from
Apache Software Foundation
• IIS modifications are made through
property pages
• Apache modifications are typically made
by changing /etc/httpd/conf/httpd.conf