Web Server Administration Chapter 6 Configuring a Web
Web Server Administration Chapter 6 Configuring a Web Server
Overview n n n Understand how a Web server works Install IIS and Apache Web servers Examine the IIS and Apache properties Host multiple Web sites Configure new Web sites in IIS and Apache Understand virtual directories
How a Web Server Works n n HTTP (Hypertext Transfer Protocol) defines how information is passed between a browser and a Web server The two most popular Web servers are n n Apache from Apache Software Foundation Internet Information Services (IIS) from Microsoft n n 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 n As is true with other servers such as DNS, Web servers listen for communication at a port n n n 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 n The current version of HTTP is 1. 1 n n 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 n This makes it more challenging to create a shopping cart application
Understanding HTTP n HTTP 1. 1 supports persistent connections n n n 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 n When the browser sends a request to a Web server, it looks like: GET /hello. htm HTTP/1. 1 Host: www. technowidgets. com n n The above requests the hello. htm file from the root of the Web server It specifies the host of www. technowidgets. com n There could be multiple hosts at the IP address
Understanding HTTP n 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 <html><body> Hello, World </body></html> n The headers contain information about the page
Features in Apache n n 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 n n Apache 2. 0 has n n n A proxy server isolates your real Web server from the Internet Better support for Windows Support for IPv 6 Simplified configuration Unicode support in Windows Multilanguage error responses Apache supports many programming languages such as Perl and PHP
Features in IIS versions associated with Windows versions n n 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 n Web Distributed Authoring and Versioning (Web. DAV) n n Named virtual hosting n n n Multiple Web sites can share a single IP address Per Web site bandwidth throttling n n Allows a server to share Web-based files Control bandwidth by Web site Kerberos authentication Secure Sockets Layer 3. 0 n Encrypted communication
Features in IIS 6. 0 n Increased security n n Expanded language support n n n Default permits only HTML documents Can use XML and SOAP Support for IPv 6 Increased dependability n n Kernel-mode HTTP service Self-healing mechanism
Components in IIS n File Transfer Protocol (FTP) server n n Front. Page 2000 Server Extensions n n n Used by programs to transfer files to and from a Web site NNTP Service n n To transfer files between user and server Used to create user forums SMTP Service World Wide Web Server
Installing Apache n n Apache can be installed when you install Linux It is also on Red Hat CD 2 If you install it from the Red Hat CD, the directories will be consistent with other server applications If you download it from the Apache Web site, you have to compile it and install it
Starting Apache n n By default, Apache does not start after you install it The following table has a list of commands Procedure Start Apache Command apachectl start Stop Apache apachectl stop Restart Apache apachectl restart
Minimal Apache Configuration n n Add a Server. Name in /etc/httpd/conf/httpd. conf Add apachectl start to /etc/rc. d/rc. local
Default Web Site Properties in IIS
Tabs on the Default Web Site Properties Dialog Box n Operators (Windows 2000) only n n Performance n n n This property lists users who can administer Web site Limit bandwidth by Web site Limit simultaneous connections (Windows 2003) ISAPI Filters n Specify applications that process HTTP requests
Tabs on the Default Web Site Properties Dialog Box n Home Directory n n Documents n n Configure the name for default Web pages HTTP Headers n n Specifies the location and properties of the root Log information here Permissions Add your own custom headers Custom Errors n Create custom pages for HTTP errors
Apache Properties. Global Environment n Server. Root n n Keep. Alive n n Directory location of server files Indicates whether Apache should maintain a persistent connection Listen n n Determines the port number for the server Default is 80
Apache Properties. Main Server Configuration n User n n n Server. Admin n n E-mail address of administrator Server. Name n n Shows the user name that Apache employs when someone requests a Web page The default is apache DNS host name or IP address of server Document. Root n Directory where the Web pages are stored
Hosting Multiple Web Sites by Port Number n n Associate each new Web site with a port above 1023 To retrieve a Web page from a site at port 8080 n n www. technowidgets. com: 8080/prod. htm Because it requires a user to add the port number, it is not a popular method
Hosting Multiple Web Sites by IP Address n You can create multiple IP addresses on a single NIC n n n Referred to as virtual IP addresses Useful for flexibility because if each domain has its own unique IP address, you can easily move the domain to a different Web server It is getting more expensive to get multiple IP addresses from an ISP
Hosting Multiple Web Sites by Host Name n n Multiple host names can be associated with a single IP address Getting a single IP address from your ISP is relatively inexpensive You can host an almost unlimited number of domains with a single IP address It is the most common method of hosting
Configuring a Virtual Host Based on an IP Address in Apache n In /etc/rc. d/rc. local, add an IP address such as: n n /bin/ifconfig eth 0: 0 192. 168. 0. 150 In the Virtual Host section of httpd. conf n <Virtual. Host 192. 168. 0. 150> Server. Name research. technowidgets. com Document. Root /var/www/research </Virtual. Host>
Configuring a Virtual Host Based on a Host Name in Apache n n Name. Virtual. Host defines the common IP address Multiple configurations repeat the same IP address and define unique Server. Name settings Name. Virtual. Host 192. 168. 0. 100 <Virtual. Host 192. 168. 0. 100> Server. Name www. technowidgets. com Document. Root /var/www/html </Virtual. Host> <Virtual. Host 192. 168. 0. 100> Server. Name web 1. technowidgets. com Document. Root /var/www/web 1 </Virtual. Host>
Configuring a Virtual Directory in Apache n The following associates the virtual directory called prod with the location of the directory Alias n /prod/ “/var/www/prod/” Then it configures the directory <Directory “/var/www/prod”> Allow. Override None Order allow, deny Allow from all </Directory>
Summary n n 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
Summary n n You can create multiple Web sites on a single computer by adding port numbers, IP addresses, and/or host names Virtual directories are directories that appear to be located beneath the root, yet are physically located elsewhere
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