Transcript Web Server Software Options

Web Server
SAS Lecture 6
Course Overview and Goals
• This course will teach you how to install, configure,
and administer a Web server that runs on a Unix
system and can be used to deliver dynamic content.
About Your Classmates…
• Introductions
• What do you do?
• What do you do with computers?
• Why are you taking this class?
How does the World Wide Web
Work?
• Works on a client/server model. The Web server is
the server component. The Web browser is the
client component. Purpose of the Web server is to
provide documents to clients.
• Web servers, Web browsers, and the information
that is shared between them through the
Hypertext Transfer Protocol (HTTP) protocol make
up the World Wide Web.
History of the World Wide Web
• Grew out of the Internet, a network of networks
designed that began in the early 1970’s and was used
to support a variety of services (including telnet, ftp,
Usenet, email, and gopher) that communicated via
TCP/IP (Transmission Control Protocol/Internet
Protocol).
• In 1989, Tim Berners-Lee at CERN developed a new
system to simplify document distribution and to allow
documents to be linked together. Called the
“WorldWideWeb.”
Web History, con’t.
• In 1993, the National Center for
Supercomputing Applications (NSCA)
released to the public a NCSA server software
and a GUI Web browser called Mosaic.
Quickly became popular.
• Mosaic became Netscape
Who is a Webmaster?
• A Webmaster is someone responsible for the
content and/or management of a Web site
and/or a Web server.
What Roles Do Webmasters Play?
• Web Designers – Create graphical
elements and determine layout of Website.
• Content Providers- Create and edit HTML
documents.
• Web Developers – Write CGI, Java,
JavaScript, ASP, PHP, and other scripts or
programs that are used to deliver dynamic
content.
Webmaster Roles, con’t.
• Administrators – Responsible for maintaining the
Web server software and often the operating
system and hardware where the Web server is
installed.
• For most organizations, these responsibilities
tend to be split over multiple job positions except
for very small and simple Web sites.
Planning Your Server
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How and where will you host it?
What kind of hardware will you use?
What kind of Operating System will the hardware run?
What Web server software will you use?
What domain name will your site use?
Answers to above questions usually determined by
budget, staffing, and existing infrastructure of your
organization.
Hosting Your Server: Use an ISP
(Internet Service Provider)
• Free Page Site – For personal use, limited space and
tools, adds advertisements. (examples: Yahoo,
Tripod, Xoom, etc.)
• Personal Page Site – For personal use, usually
included with dialup account (about $20 per month), 220 MB disk space, none or limited access to serverbased technologies for delivering dynamic content,
generally under your ISP’s domain. (Website URL
usually looks something like:
http://www.yourisp.com/~yourusername)
Hosting Your Server, con’t.
• Virtual Host – For business or personal use, share a
machine with other domains, can use your own
domain (http://www.yourdomain.com), should provide
a fairly wide range of tools for building more complex
Websites, costs based on disk usage and traffic,
ranges from $10 to several hundreds of dollars a
month. Generally available through all ISPs and
Hosting-only providors such as Highway Technologies
(http://www.hway.net) and YourDomainHost
(http://www.yourdomainhost.com)
Hosting Your Server, con’t.
• Dedicated Server – For business use, ISP owns and
runs the machine, your organization dictates the
configuration and has exclusive access to the system,
expensive.
• Co-Located Server – For business use, your
organization owns the hardware and software and is
responsible for maintaining it, ISP houses the system
and provides a network connection, pricing
determined by bandwidth requirements.
Hosting Your Server: Do It Yourself:
Networking Options
• For an Intranet Server– Need a LAN (local area network).
• For an Internet Server – Need a dedicated Internet connection.
Internet Connectivity Options:
• POTS (up to 56Kbps) – not practical for business use
• ISDN (128Kbps) – only a good choice if cable or DSL is not
available
• Cable (512Kbps – 10Mbps)
• DSL (128kps – 1.54 Mbps+)
• T-1 (up to 1.54Mbps) – full, fractional, or burstable
• T-3 (up to 45 Mbps)
Finding an ISP
• Setting up a Internet Web site will require you
to purchase some level of services from an
ISP.
• The List – http://thelist.com
Hosting Your Server: Hardware
Options
• Need to select a machine architecture (i.e Intel
Compatible PC, Sun, Macintosh G4).
• Processor speed and number of processors.
• RAM and Disk Space.
• NIC card.
• Price can range from several hundred dollars to
thousands of dollars.
Hosting Your Server: Operating
System Options
• Commercial Versions of Unix (i.e. Solaris, Irix, HPUX, AIX, MacOS X).
• Free Versions of Unix (i.e. Linux, FreeBSD).
• Microsoft Windows (9x, NT, Windows 2000).
• Novell NetWare
• Windows vs. Unix – raises issues of easy of use,
stability, scalability, open source, and pricing.
Hosting Your Server: Web Server
Software Options
• According to the Netcraft Web Server Survey
(http://www.netcraft.com), as of January 2000, three
Web server software distributions support over 90% of
all Web servers on the Internet:
• Apache 61.66%
• Microsoft Internet Information Server 19.63%
• Netscape Enterprise 7.22%
Web Server Software Options:
Apache
• “The standard” for UNIX web servers.
• Originally based on NCSA httpd code.
• Can be installed under most Unix variants and
Windows. Binary versions available for many
operating systems.
• Uses file-based configuration, although GUI tools are
also available.
Introduction to Apache, con’t.
• Unix versions very stable. Windows version less
mature (beta-level code).
• Very Fast and uses resources efficiently.
• Freely distributed source code. Can be modified for
commercial or non-commercial use.
• Price: Free
• See http://www.apache.org for more information.
Web Server Software Options:
Netscape Server
• Sometimes referred to as the iPlanet server
• Distributed through Sun-Netscape Alliance called
iPlanet.
• Server packages: iPlanet/Netscape Enterprise Server,
Netscape Fast-Track Server.
• Runs under Windows NT, Solaris, Irix, HP-UX, Digital
Unix, AIX, Linux (coming soon).
Netscape iPlanet Server, con’t.
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Uses Web-based administration.
Can be resource intensive.
Price: $1495 per processor for Enterprise Server
See
http://www.iplanet.com/products/infrastructure/web_se
rvers for more information.
Web Server Software Options:
Microsoft Internet Information
Server
• Most popular for NT-based web servers.
• Runs only under Windows NT Server. IIS v4 is the
most popular release. IIS v5 was released with
Windows 2000 Server.
• GUI-based administration. Web-based administration
available as well.
• May not scale well.
Microsoft IIS, con’t.
• Source code not available. Extendable through
Microsoft’s Internet Server API (ISAPI).
• Price: Free with NT Server 4.0
• See
http://www.microsoft.com/ntserver/web/default.as
p for more information.
Important Notes about Web Server
Hardware
• Web Servers need fast disk access and a lot of RAM
to handle high-volumes of traffic.
• Not unusual to see web servers with 1GB of RAM
and 10,000RPM hard drives.
• Processor speed and performance becomes very
important when delivering dynamic content via CGI
scripts, Server Side Includes or other web
applications.
Uniform Resource Locator (URL)
• URL: a fancy way of saying “web site
address”
• Anatomy of a URL:
http://internet.rutgers.edu:80/ITI520/index.html
Protocol
Hostname
Port Number
Path To File
HTTP – An Introduction
• HTTP – The Hypertext Transfer Protocol
• The protocol used between web clients (browsers)
and web servers.
• Web browsers “ask” for a specific web page from
the server, who returns the content
What do HTTP Requests Look Like?
GET /images/penguin.gif HTTP/1.0
User-Agent: Mozilla/0.9.4 (Linux 2.2.19)
Host: www.kernel.org
Accept: text/html, image/gif, image/jpeg
Accept-Encoding: gzip
Accept-Language: en
Accept-Charset: iso-8859-1,*,utf-8
Cookie: B=xh203jfsf; Y=3sdkfjej
<cr><lf>
• Messages are in ASCII (human-readable)
• Carriage-return and line-feed indicate end of headers
• Headers may communicate private information
• (e.g., browser, OS, cookie information, etc.)
Web Servers: Implementation
and Performance
Erich Nahum
28
What Kind of Requests are there?
Called Methods:
• GET: retrieve a file (95% of requests)
• HEAD: just get meta-data (e.g., mod time)
• POST: submitting a form to a server
• PUT: store enclosed document as URI
• DELETE: removed named resource
• LINK/UNLINK: in 1.0, gone in 1.1
• TRACE: http “echo” for debugging (added in 1.1)
• CONNECT: used by proxies for tunneling (1.1)
• OPTIONS: request for server/proxy options (1.1)
Web Servers: Implementation
and Performance
Erich Nahum
29
What
Do
Responses
Look
Like?
HTTP/1.0 200 OK
Server: Tux 2.0
Content-Type: image/gif
Content-Length: 43
Last-Modified: Fri, 15 Apr 1994 02:36:21 GMT
Expires: Wed, 20 Feb 2002 18:54:46 GMT
Date: Mon, 12 Nov 2001 14:29:48 GMT
Cache-Control: no-cache
Pragma: no-cache
Connection: close
Set-Cookie: PA=wefj2we0-jfjf
<cr><lf>
<data follows…>
• Similar format to requests (i.e., ASCII)
Web Servers: Implementation
and Performance
Erich Nahum
30
What Responses are There?
• 1XX: Informational (def’d in 1.0, used in 1.1)
100 Continue, 101 Switching Protocols
• 2XX: Success
200 OK, 206 Partial Content
• 3XX: Redirection
301 Moved Permanently, 304 Not Modified
• 4XX: Client error
400 Bad Request, 403 Forbidden, 404 Not Found
• 5XX: Server error
500 Internal Server Error, 503 Service
Unavailable, 505 HTTP Version Not Supported
Web Servers: Implementation
and Performance
Erich Nahum
31
Installation
• The Apache2 web server is available in Ubuntu
Linux. To install Apache2:
• At a terminal prompt enter the following
command:
sudo apt-get install apache2
Configuration
• Global Configuration
/etc/apache2/apache2.conf
• Ports configuration
/etc/apache2/ports.conf
• Virtual Host configuration
/etc/apache2/sites-available/
Copy file : 000-default.conf
to
sitename.conf
(example, siam.adser.com.conf)
• Add symlink to /etc/apache2/sites-enable/ :
sudo a2ensite siam.adser.com.conf
Vitual Hosts Configuration
/etc/apache2/sites-available/ siam.adser.com.conf :
<VirtualHost 192.168.56.101:80> //IP add and port
ServerAdmin [email protected]
ServerName siam.adser.com
ServerAlias www.siam.adser.com
DocumentRoot /var/www/html/siam.adser.com/
ErrorLog ${APACHE_LOG_DIR}/error.log
CustomLog ${APACHE_LOG_DIR}/access.log combined
</VirtualHost>
//loc. index
Security
• TLS/SSL
TLS, or transport layer security, and its
predecessor SSL, secure sockets layer, are secure
protocols created in order to place normal traffic in a
protected, encrypted wrapper.
• Enable ssl
sudo a2enmod ssl
Generate Key
sudo openssl req -x509 -nodes -days 365 -newkey
rsa:2048 -keyout /etc/apache2/ssl/apache.key -out
/etc/apache2/ssl/apache.crt
• penssl: This is the basic command line tool
provided by OpenSSL to create and manage
certificates, keys, signing requests, etc.
• req: This specifies a subcommand for X.509
certificate signing request (CSR) management.
• -x509: This option specifies that we want to make a
self-signed certificate file instead of generating a
certificate request.
The rsa:2048 tells OpenSSL to generate an RSA key that is 2048 bits long.
The rsa:2048 tells OpenSSL to generate an RSA key that is 2048 bits long.
• nodes: This option tells OpenSSL that we do not
wish to secure our key file with a passphrase.
• -days 365: This specifies that the certificate we are
creating will be valid for one year.
• -newkey rsa:2048: The rsa:2048 tells OpenSSL to
generate an RSA key that is 2048 bits long.
• -keyout: This parameter names the output file for
the private key file that is being created.
• -out: This option names the output file for the
certificate that we are generating.
Configure host ssl
• /etc/apache2/sites-available/default-ssl.conf
<IfModule mod_ssl.c>
SSLEngine on
SSLCertificateFile /etc/apache2/ssl/apache.crt
<VirtualHost _default_:443>
SSLCertificateKeyFile /etc/apache2/ssl/apache.key
ServerAdmin [email protected]
<FilesMatch "\.(cgi|shtml|phtml|php)$">
SSLOptions +StdEnvVars
ServerName your_domain.com
</FilesMatch>
<Directory /usr/lib/cgi-bin>
ServerAlias www.your_domain.com
SSLOptions +StdEnvVars
DocumentRoot /var/www/html
</Directory>
BrowserMatch "MSIE [2-6]" \
ErrorLog ${APACHE_LOG_DIR}/error.log
nokeepalive ssl-unclean-shutdown \
CustomLog ${APACHE_LOG_DIR}/access.log combined
downgrade-1.0 force-response-1.0
BrowserMatch "MSIE [17-9]" ssl-unclean-shutdown
</VirtualHost>
Configure host ssl
• Enable SSL configuration on site
• sudo a2ensite default-ssl.conf
• Restart apache service
• sudo service apache2 restart
• Open your site
• https://server_domain_name_or_IP
End Slides…
• Practice make perfect…
• Any question?