web servers web server software is a product that works with the operating system the server...
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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 Platforms-Microsoft
• 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
XML
• Commerce Server– Builds e-commerce sites in a short amount of
time
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
environment
• 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 port– 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
Host: www.technowidgets.com
• The above requests the hello.htm file from the root of the Web server
• It specifies the host of www.technowidgets.com– 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 OKServer: Microsoft-IIS/5.0Content-Type: text/htmlLast-Modified: Fri, 17 May 2005 18:21:25 GMTContent-Length: 43<html><body>Hello, World</body></html>
• The headers contain information about the page
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
Internet
• 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 versions– 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 (WebDAV)– 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
site
• 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 permissions
File System Permissions in Windows
Permission Description
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
Modify Allows read, write, and delete
Read With this permission, you can read files but cannot execute them
Write 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
only)
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 Sitesby Port Number
• Associate each new Web site with a port above 1023
• To retrieve a Web page from a site at port 8080
• www.technowidgets.com:8080/prod.htm
• Because it requires a user to add the port number, it is not a popular method
UNIX/Linux
• 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
mechanisms– Shell – provides user interface
Linux
• Source code is freely available– Developers can make changes
• Available from a number of organizations– Red Hat– Mandrake– SuSe
Summary
• Server administration focuses on LANs• Web server administration focuses on the
Internet• 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
Summary
• Web servers use HTTP to send HTML documents
• 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