WMB-520: Web Technology Web Server Setup

1
WMB-520 Web TechnologyWeb Server Setup
Meeting 1 Introduction to the Internet, World
Wide Web and Web Servers

• Rutgers University Center for Applied Computing
  Technology
• Instructor Christopher Uriarte

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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.
• The course objectives will be achieved through a
  combination of lectures, demonstrations, and
  hands-on exercises.

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About Your Instructor

• Chris Uriarte chrisjur_at_cju.com. Feel free to
  contact me anytime via email.
• Homepage for this class linked from
• http//www.cju.com/classes
• Contains all slides, notes and misc. links and
  resources.

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What This Course Is and Is Not

• The purpose of the course is to teach you the
  concepts behind serving content on the web and
  how to run and administer web server software on
  a UNIX system. This means you will be learning
  how to use tools to deliver content for the World
  Wide Web, not to create content.
• Rutgers offers other courses designed to teach
  you how to create content for the World Wide Web
  (HTML design, Perl, etc.)

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Prerequisites

• Familiarity with a Web browser such as Netscape
  or Internet Explorer.
• You MUST have user-level experience with UNIX and
  must be familiar with the use of a UNIX text
  editor like vi, emacs and pico

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Class Schedule

• Week 1 Introduction to the Internet, the World
  Wide Web, and Web Servers
• Week 2 Installing and Configuring the Apache Web
  Server
• Week 3 Extending Apache Advanced Topics
• Week 4 More advanced configuration and Web
  Security
• Note classes 2-4 are hands-on classes.

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Course Resources

• Textbook Apache The Definitive Guide by
  Laurie, Laurie and Denn (OReilly Press, 1999).
• User account on UNIX server blender.rutgers.edu.
  (Remote access available via SSH)
• Slides and resources on class hompage, linked
  from http//www.cju.com/classes/

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How does the World Wide Web Work?

• Works on a client/server model The Web server
  software 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.

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History of the World Wide Web

• Grew out of the Internet, a network of networks
  that began in the early 1970s and was used to
  support a variety of services (including telnet,
  ftp, Usenet, email, and gopher). Most of these
  services communicated via 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
  World Wide Web.

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Web History, cont.

• In 1993, the National Center for Supercomputing
  Applications (NSCA) released to the public the
  NCSA Web Server software and a GUI Web browser,
  called Mosaic. Quickly became popular.
• Mosaic became Netscape first major web browser
  distribution.

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The Web Today

• The Web has evolved greatly since it was first
  implemented, but its overall architecture has
  remained generally the same.
• Still fueled by three major components A
  network (typically the Internet, but can also
  include local networks or Intranets), a client
  component (a web browser) and a server software
  component (what were going to learn about in
  this class).

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Webmasters, Sys-Admins and Developers, Oh My!

• There are a number of key roles that are
  necessary to support a web infrastructure.
  Providing end-to-end web services requires
  knowledge about systems, network, software,
  graphical design, programming and much more.
• There are many different

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Roles in the Web World

• Web Designers Create graphical elements and
  determine layout of Website.
• Content Providers- Create and edit HTML
  documents.
• Web Developers Write web applications using
  programming languages such as Java, JavaScript,
  ASP, PHP and Perl other used to deliver dynamic
  content.

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Roles in the Web World (cont)

• System Administrators Responsible for
  maintaining the Web server software and often the
  operating system and hardware where the Web
  server is installed.
• Network Administrators Responsible for the
  design and maintanance of network components used
  to deliver web content.
• For most organizations, these responsibilities
  tend to be split over multiple job positions
  except for very small and simple Web sites.

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Hosting A Website The Planning Phase

• There are a number of key questions an
  organization or individual must ask when planning
  to deploy a website
• 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.

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Hosting Your Website Options

• Use a Free Page Site For personal use, limited
  space and tools, typically adds advertisements.
  (examples Yahoo, Tripod, Xoom, etc.).
  Limitation on amount of traffic your site is
  allowed. Generally not an option for business
  use.
• Personal Page Site For personal use, usually
  included with an ISP (about 20 per month),
  includes small amoung of disk space, no or
  limited access to server-side technologies for
  delivering dynamic content, generally uses your
  ISPs Internet domain name. Limitation on amount
  of traffic your site is allowed. (Website URL
  usually looks something like http//www.yourisp.c
  om/yourusername). Might be an option for very
  small businesses.
• Under both models, ISP owns and manages the
  server, network and web server software. You
  simply provide the content.

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Hosting Your Website, cont.

• Virtual Hosting Most popular web hosting option
  todays. Suitable for business or personal use.
  Using this model, an ISP uses one machine to host
  many different websites (sometimes called shared
  hosting). You can use your own Internet domain
  name (http//www.yourdomain.com). These
  typically provide a wide range of tools for
  building more complex Websites.
• ISP owns and manages the server, network and web
  server software. You simply provide the content.
• Overall cost based on disk usage and website
  traffic, ranges from 20 to several thousands of
  dollars a month. Now generally available through
  all ISPs and specialized Hosting-only providers
  such as Highway Technologies (http//www.hway.net)
  and YourDomainHost (http//www.yourdomainhost.com
  )

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Hosting Your Website, cont.

• Dedicated Server Services For business use, ISP
  owns and the hardware and network. Your
  organization typically has the option of managing
  and configuring the server. You provide the
  content. Your organization has exclusive access
  to the server.
• Price based on the type of server you require and
  the amount of traffic your site uses.
• Co-Location Services (co-lo) For business use
  - Your organization owns and manages the
  hardware, software and content. ISP provides you
  with space to place the server and the network
  connectivity.
• Price based on the amount of space your servers
  require, the power requirements of the servers
  and the amount of traffic.

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Hosting Your Website, cont.

• Managing your Own Web Server Network (in-house
  web hosting) You provision, configure and
  manage the network connection, hardware, software
  and provide the content.
• Most flexible option you have complete control.
• Cost can be very high or very low depending on
  the business need.

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Hosting Your Web Server Do It Yourself
Networking Options

• For an Intranet Server Need a LAN (local area
  network). Does not require an Internet
  connection.
• For an Internet Server Need a dedicated
  Internet connection. Internet Connectivity
  Options
• POTS (up to 56Kbps) not practical for web use
  anymore.
• ISDN (128Kbps) not practical for web use either
  (costly, slow)
• Cable (512Kbps 10Mbps)
• DSL (128kps 1.54 Mbps)
• T-1 (up to 1.54Mbps) full, fractional, or
  burstable
• T-3 (up to 45 Mbps) full, fractional, or
  burstable

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Finding an ISP

• Some ISPs specialize in web hosting and provide
  all the service described earlier (shared
  hosting, dedicated server, co-location, etc.).
• Other ISPs specialize only in commercial Internet
  access (AOL, Earthlink, etc.). They may provide
  free personal website space.
• Check The List http//thelist.com, for a
  comprehensive list ISPs and their services.

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Hosting Your Server Hardware Options

• There are a number of things to consider when
  choosing the hardware platform for your website
• Need to select a machine architecture (i.e Intel
  Compatible PC, Sun, Macintosh) Typically
  dictated by your Operating System of choice
• Processor speed and number of processors.
• RAM and Disk Space.
• NIC card.
• Price can range from several hundred dollars to
  thousands of dollars.

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Web Server Hardware Myths vs. Realities
Myth
Reality
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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
  custom web application.
• High-end PCs can typically handle 100K website
  visits per day.

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Hosting Your Server Operating System Options

• Commercial Versions of Unix (i.e. Solaris HP-UX,
  AIX, MacOS X, IRIX).
• Free Versions of Unix (i.e. Linux, FreeBSD).
• Microsoft Windows (9x, NT, XP, Windows 2000).
• Windows vs. Unix raises issues of easy of use,
  stability, scalability, open source, and pricing.
  UNIX platforms generally considered more
  reliable, scaleable and cost-effective.

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Hosting Your Server Web Server Software Options

• The primary focus of this class will be
  installing and configuration the web server
  software the software the turns an ordinary
  computer into a computer that can host and serve
  content on the World Wide Web.
• Web server software is often referred to as
• The Web server
• The web daemon
• The httpd

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Hosting Your Server Web Server Software Options

• According to the Oct. 2002 Netcraft Web Server
  Survey (http//www.netcraft.com), four Web server
  software distributions support over 90 of all
  Websites on the Internet
• Apache - 65
• Microsoft Internet Information Server - 25
• Zeus Web Server - 1.4
• iPlanet 1.3

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Web Server Software Options Apache

• The standard for UNIX web servers..
• The most popular web server. Considered to be
  the most secure, stable and robust server
  platform.
• 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 some GUI
  tools are also available.

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Introduction to Apache, cont.

• Unix versions very stable. Windows version less
  mature, but becoming more stable. Apache 2.0 is
  released.
• Very Fast and uses resources efficiently.
• Freely distributed source code. Can be modified
  for commercial or non-commercial use.
• Price Free. Developed by the Apache software
  foundation.
• See http//www.apache.org for more information.

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Web Server Software Options SunOne/iPlanet/Netsc
ape Server

• Now officially called the SunOne Web Server
• Originally developed as Netscape Server, then
  distributed by partnership between Sun/Netscape,
  now owned and supported by Sun.
• Server packages iPlanet/Netscape Enterprise
  Server, Netscape Fast-Track Server.
• Runs under Windows NT, Solaris, HP-UX, Digital
  Unix, AIX, Linux.

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Netscape/SunOne Server, cont.

• Uses Web-based administration.
• Can be resource intensive.
• Lost major portion of market over last 5 years.
• Price 1495 per CPU
• http//wwws.sun.com/software/products/web_srvr/hom
  e_web_srvr.html for more information.

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Web Server Software Options Microsoft Internet
Information Server (IIS)

• Most popular for Win NT and 2000-based web
  servers.
• Version 4 runs on Windows NT Server. IIS version
  5 runs on Windows 2000 Server (and XP, but used
  for development purposes only).
• GUI-based administration. Web-based
  administration available as well.
• May not scale well.

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Microsoft IIS, cont.

• Increasing concerns over its security.
• Source code not available. Extendable through
  Microsofts Internet Server API (ISAPI).
• Price Free with NT Server 4.0 and Windows 2000
  Server
• See http//www.microsoft.com/windows2000/technolog
  ies/web/default.asp for more information.

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How the Internet Works Networking Basics

• For a Web server to be useful needs to be
  attached to a network.
• Minimum requirements for a computer network at
  least two computers that have a media and a
  method of communicating.
• All Internet applications use TCP/IP
  (Transmission Control Protocol/Internet Protocol)
  for low-level communications.

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Networking Basics TCP/IP

• TCP/IP is actually a combination of 2 protocols
• A transport layer protocol called the
  Transmission Control Protocol (TCP)
• A network protocol called the Internet Protocol
  (IP)

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Networking Basics IP Addresses

• TCP/IP uses IP address to identify different
  devices. Every computer on the Internet must have
  a least one unique IP address.
• IPv4 IP address are four 8-bit numbers separated
  by dots 165.230.30.68
• Usually divided in three parts
• 165.230 is one of Rutgers networks e.g. no one
  else has addresses starting with 165.230
• 30 is the subnet portion of the address
• 68 is the particular node, or host portion of the
  address
• Division not necessarily on octet boundary.

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TCP/IP Two Friends, Working Together

• IP - An IP address represents a machines
  identity on the internet and tells other machines
  how to get to it similar to your street address
  (e.g. 123 Main Street, Anytown, USA).
• TCP is a mechanism used to ensure that anything
  sent to a specific IP address makes it there in
  one piece. similar to the Post Office.
• Together, TCP/IP assures that anything sent to a
  server on the Internet is delivered to the right
  place in one complete piece.

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Networking Basics IP Addresses

• IP addresses no longer being distributed by
  classes blocks are distributed to ISPs on an
  as-needed basis and must be justified.
• IP addresses are hard to come by. How do you get
  them?
• Your ISP received an address space from the
  ARIN (http//www.arin.org)
• You receive IP addresses from your ISP.

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Networking Basics Tools

• Network interfaces need to be assigned IP
  addresses.
• Interfaces can be configured using ifconfig
  command on UNIX machines.
• Type ifconfig a to view current configuration
  settings.
• Additional tools for network monitoring ping,
  traceroute, tcpdump, netstat, arp, snoop.

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Networking Basics DNS

• IP addresses are usually paired with more
  human-friendly names The system that contains the
  IP Address-to-Hostname pairing is called the
  Domain Name System (DNS).

internet.rutgers.edu
Hostname Organization Top-level domain

• Other top-level domains include .com, .gov, .org,
  etc. There are also country-specific domains
  like .uk, .ca, .jp, etc.

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Networking Basics DNS, cont.

• Domain name information is maintained through a
  distributed database of host name/ IP address
  pairing.
• The Network Information Center (NIC) manages the
  top-level domains and maintains a database of
  registered name servers for all domain names.
• Host name assignments maintained through zone
  files on primary and secondary DNS servers
  controlled by the organization that owns the
  domain (or their ISP).

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Networking Basics DNS, cont.

• Network Solutions (previously the InterNic)
  registers domain names See http//www.networksol
  utions.com. Other registrars include
  Register.com
• Costs range from 20 to 50 per year.
• ISPs often offer domain name registration as
  part of other packages (such as web hosting
  packages).
• Need to register a primary and secondary domain
  name servers for your domain and arrange to have
  zone files created on DNS servers. Your ISP
  will typically configure this for you.

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DNS Overview If Computers on the Internet Could
Talk
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Networking Basics DNS Tools

• There are several tools for for monitoring DNS
  information
• whois tells you the owner and primary DNS
  servers associated with a domain (e.g. whois
  yahoo.com). Also available via web browser at
  www.networksolutions.com.
• nslookup and host tell you IP address
  information for a particular hostname on the
  internet (e.g. nslookup www.yahoo.com or host
  www.rutgers.edu)

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DNS Exercise

• What are IP addresses of the DNS servers that
  contain information about rutgers.edu?
• What are the IP address of
• www.retaildecisions.com
• abusaday.admin.cju.com
• www.linux.org

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Networking Basics Ports

• Servers tend to run a number of services. A
  single NIC can be used to provide multiple
  services through ports.
• Network server software listens on specific
  ports. Clients contact server by specifying an IP
  address and a connection port. The port is the
  identifier that tells a server what application
  a piece of network traffic is destined for.
• Common services and port numbers
• smtp 25, ftp 21, telnet 23, http/web 80,
  https/ssl 443
• A list of services and ports is contained in the
  /etc/services file on UNIX systems.
• Ports below 1024 are reserved for special system
  services and can only be used by programs started
  by root (the system administrator on a UNIX
  system).

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Uniform Resource Locator (URL)

• URL a fancy way of saying web site address
• Anatomy of a URL

http//internet.rutgers.edu80/ITI520/index.html
Protocol Hostname Port Number Path To
File
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Unix Tools and Commands

• File Editors vi, emacs, pico
• File system navigation cd
• File management mv, rm, mkdir,rmdir, ls, chmod,
  ln
• Archiving and compression tar, gzip
• Process management ps, kill
• Man pages available for all these commands, e.g
  man rmdir

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UNIX Process Management

• UNIX Processes are managed using the ps and kill
  commands
• ps is used to list processes running on the
  system
• kill is used to kill and restart processes
  running on the system
• Every time you start a new program (pico, vi,
  bash, etc.) a process is created and you are the
  owner of that process.
• Each process is assigned a unique Process ID
  (PID) on the system

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Process Management Exercises

• You can type ps aux to see all the processes
  running on a system. This will list the process
  owner, process ID (PID) and the command being
  run.
• You can kill any PID, as long as you are the
  owner of the process.
• ps aux grep username will show all the
  processes your are currently running

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Process Management Exercises, cont.

• Open up a new UNIX terminal window and type vi
  foo.txt. This will create a new process on the
  system that you own.
• Open a second terminal window on the same UNIX
  system. Locate the process ID for your vi
  session and kill it. What happens?

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Reading for Next Week

• As assigned in class