Server Basics and Web Server Administration

Report
2440: 141
Web Site Administration
Web Server Basics and Administration
Instructor: Enoch E. Damson
Server Administration
 Common tasks of server administrators include:
 Focusing on the LAN
 Provide access to software and services
 Make sure that the user environment is reliable and
consistent
 Minimize harm that users can do to network
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Server Administration…
 Working with Users:
 Users are central to server administration because:


Users need to be productive
Users like consistency
 Roaming profiles – allow users to have the same personalized
desktop environment on multiple computers
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Server Administration…
 Establishing Access Control:
 Users need just enough access to do their jobs
 Typically, users are organized into groups
 The groups are given access to network resources
 Users can be given different access to the same resources
 A document can be read by everyone but modified by only specific
people
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Server Administration…
 Understanding the Server Environment:
 All but the smallest network includes more than one server
 With Windows computers, servers and users’ computers
can be organized into domains in order to centralize control

Users log on to a domain, which can be completely separate from
or related to other domains
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Web Server Administration
 Web server administrators focus on the Internet
 Need to work with ISPs and Web page developers
 Typically, a Web server provides information to anyone
who requests it over the Internet
 Web servers can contain other applications such as FTP, email, DNS, etc
 Technical skills are needed to administer a Web server in
order to:
 Control access to Web pages
 Create virtual Web sites on a single server
 Make sure programming environment and other services are
running correctly
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Web Server Administration…
 Depending on the size of the organization, some tasks of
Web server administrators may be delegated
 Systems maintenance
 E-mail administration
 Security implementation
 Web page development
 Database design
 Programming
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Web Server Administration…
 Understanding the Web Environment:
 Web server administrators work with Web developers and
other network administrators
 Web Servers administrators control Internet users’ access
to Web servers

It is impossible to control the Internet
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Web Server Administration…
 Selecting Programs:
 Web server administrators need to install programs and
services



Programs – solve specific problems
Service (daemon) – programs that run in the background
Web service – one or more programming modules that reside on
a Web server and can be accessed from client computers
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Web Server Administration…
 Selecting Server-Side Programs:
 Web developers use a variety of server-side programming
languages






Perl – one of the 1st languages for dynamic Web pages
Active Server Pages (ASP) – interprets programs written using VBScript or
JavaScript
ASP.Net – compiles programs written using Visual Basic.NET, C#.NET (similar
to C++), J#.NET (similar to Java)
Java Server Pages (JSP) – compiles programs written using Java into Java
servlets
PHP Hypertext Preprocessor (PHP) – has structure similar to ASP and JSP
and syntax similar to Perl and Java
ColdFusion – has syntax similar to ASP and JSP
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Web Server Administration…
 Selecting Databases:
 Database – a collection of data about related entities
 Database management system (DBMS) – software used to
store and manipulate data used on Web pages

Examples include:

For large sites – Oracle, MySQL, MS SQL Server, DB2, MS Access, etc
 Structured Query Language (SQL) – the language used in a
Relational DBMS to create, store and manipulate databases
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Web Server Administration…
 Managing E-mail Servers:
 Email servers are open by design to accept e-mail from
anyone
 Spam can be a problem to manage

Specific utilities can be used to help minimize spam
 Viruses are commonly sent by e-mail

Use virus detection software and keep it updated
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Web Server Administration…
 Working with Other Web Applications:
 Firewall
 Helps protect your Web server environment from attack
 FTP (File Transfer Protocol)
 A service that allows users to download files from and upload files to
a server
 DNS (Domain Name Service)
 Translates host names such as www.technowidgets.com to an IP
address
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Web Server Administration…
 Managing the Internet Connection:
 The Web administrator needs to maintain a connection to
the Internet
 The Web administrators responsibility ends at the
connection the Internet

Additional supported is handled by the ISP, who may also have to
contact a local phone company
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Administrators' Common Tasks
and Services
 Server administrators and Web server administrators
share several common tasks such as:
 Installing and configuring systems
 Maintaining security
 Monitoring the system
 Maintaining and backing up systems
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System Installation and
Configuration
 Web administrators determine the hardware and
software requirements of the system environment
 Both Server and Web server administrators install and
configure software
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Security Maintenance
 Physical and software security must both be considered
against:
 Internal security breaches
 External security breaches
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System Monitoring
 Systems are monitored to track performance,
troubleshoot problems and usage using:
 Software tools
 Log files
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System Maintenance and
Backup
 Systems must be periodically updated to take care of
security loopholes and other possible software
malfunctions
 Backing up systems is vital for both server and Web server
administrators
 Systems may have to be reconfigured due to some severe
problems
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Network Building Blocks
 Systems administrators need to understand parts of a
network and how they work together to help:
 Create an efficient and balanced network
 Prevent system disruptions from hackers
 Web server administrators need to look at networks
as a:
 Logical model – to understand how computers
communicate
 Physical structure – to understand network parts
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Network Building Blocks…
 To understand network communication, the following
models are used:
 Open Source Interconnection (OSI) model
 Transmission Control Protocol/Internet Protocol (TCP/IP)
model

Protocol - set of communication rules
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The OSI Model
 A theoretical definition of the parts of network data
communication
 Developed in the 1970s and implemented in the 1980s
 Depicts seven layers that depict how the networking
protocols function and separate the communication tasks
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The OSI Model…
Layer
Name
Description
7
Application
Responsible for low-level application access to the network.
6
Presentation
Can convert data into a format that is understandable to the Application
layer.
5
Session
Can open, maintain, and shut down communication.
4
Transport
Responsible for transporting the data from one computer to another. (TCP
and UDP)
3
Network
Primarily responsible for addressing between two computers. (IP and
ICMP)
2
Data Link
Responsible for the interface between the packets coming down through
the upper layers and the physical layer.
1
Physical
Responsible for transferring the data to the network medium.
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The TCP/IP Model
 A real-world model showing how the TCP/IP protocols
actually work
 Does not correspond exactly with the common but
theoretical OSI model
 Depicts network data communication in four layers instead
of the seven layers of the OSI model
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The TCP/IP Model…
Layer
Name
Common
Components
OSI
Reference
4
Application
HTTP, SMTP, POP3
FTP, DNS
Application
Presentation
Session
3
Transport
TCP, UDP
Transport
2
Network
IP, ICMP
Network
1
Physical
Ethernet, FDDI
Data Link
Physical
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TCP/IP Protocols
 Components of the application layer level of the TCP/IP
model include:
 Hypertext Transfer Protocol (HTTP)

Web servers implement this protocol
 Simple Mail Transfer Protocol (SMTP)

Used by e-mail servers (and sometimes Web servers) to send email
 Post Office Protocol Version 3 (POP3)

Used to retrieve e-mail
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TCP/IP Protocols…
 Other components of the application layer of the
TCP/IP model include:
 File Transfer Protocol (FTP)
 Transfers files to and from server
 Domain Name Service (DNS)
 Translates host names to IP addresses and IP addresses to host
names
 BIND (Berkeley Internet Name Domain) – the most popular program
used to implement DNS

Microsoft also has a DNS server
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TCP/IP Protocols…
 Components of the transport layer of the TCP/IP model
include:
 Transmission Control Protocol (TCP)
 Creates a reliable connection between two computers
 User Datagram Protocol (UDP)
 Does not establish a connection, just sends messages
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TCP/IP Protocols…
 Components of the network layer of the TCP/IP model
include:
 Internet Protocol (IP)
 Provides addressing scheme
 Internet Control Message Protocol (ICMP)
 Provides error messages
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Common Network Components
 Components of the physical layer of the TCP/IP
model include:
 Ethernet – the most common network technology which
connects multiple devices
 Switch – central device that allows PCs to communicate
with one another

A data cable connects the network interface card (NIC) of each
computer to the switch
 Router – forwards data packets across computer networks
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Simple Network Diagram
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Connecting to the Internet
 Connecting to the Internet requires:
 Internet Service Provider (ISP) – company that helps
connect to the Internet
 Wide Area Network (WAN) connection – used between a
building and the ISP

T-Carrier connection is often used
 A digital connection for voice and data
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Connecting to the Internet…
 Other types of Internet connections are:
 Integrated services digital network (ISDN)



Digital service using a terminal adapter (TA) or ISDN modem
Dial-up access
Offers 2 types of services:


Basic Rate Interface (BRI) – provides 3 channels (2 “B” or “Bearer”
channels and a “D” or “Delta” channel) of data transfer
Primary Rate Interface (PRI) – uses 23 B channels and 1 D channel to
provide higher amounts of bandwidth
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Connecting to the Internet…
 Other types of Internet connections are:
 Digital Subscriber Line (DSL)
 Provides higher speeds of data transfer over telephone lines
 Signal degradation is a limitation to DSL
 Types of DSL connections include:




Asymmetric DSL (ADSL)
ISDN DSL (IDSL)
Rate Adaptive DSL (RADSL)
Single DSL (SDSL)
 Cable Modem
 Shared access cable provided by cable TV company
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Planning on Web Hosting
 Some decisions about Web site hosting include:
 Hosting the Web site
 Hosting the Web server
 Hardware/software considerations
 Sizing the server (performance requirements)
 Registering a domain name
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Hosting a Site
 There are many options to consider when deciding how
to set up your Web site
 Some of the popular options include:
 ISP personal page
 Standard virtual hosting
 Co-located server
 Dedicated server
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ISP Personal Page
 Good for personal use
 Pros:
 Free
 Cons:
 Cannot have your own domain name
 Limited space
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Standard Virtual Hosting
 Allows you to have your own domain but must share
a machine with other domains
 Ideal for less custom server-side programming Web
applications
 Pros:
 Cheap way to have your own domain
 No server to maintain
 Cons:
 Server shared with many other people
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Co-Located Server
 Having your own server located at the company that
does your Web hosting (Internet Service Provider –
ISP)
 Pros:
 Control over entire server
 Faster network
 Cons:
 You still have to purchase and manage the machine
 Hardware is offsite
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Dedicated Server
 Having your own server
 Pros:
 Flexibility of having your server
 Cons:
 You still have to administer the machine
 May cost more
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Hosting a Web Server
 Some of the resources needed to host a server
include the following:
 An ISP to provide a network connection
 Hardware/Software consideration
 Operating system
 A server machine and a model or other network interface
 An IP address for the machine to make it accessible on the
network
 A domain name – but not required
 A router or other network hardware
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Sizing a Web Server
 Running your own server requires looking at
performance problems such as:
 Too much traffic on network
 Is the server running near capacity?
 A good ISP should have plenty of network bandwidth
 Bandwidth – the capacity or speed of a network expressed
in bits per second (bps)
 Throughput – amount of data that can move from one
place to another in a time period
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Bandwidth & Network Capacity
 A network bandwidth may be slowed if:
 Many clients are continuously requesting pages
 Large files are being downloaded
 To get a feel of how many people are visiting your
site, the Web server log files should be checked
 Each page requested counts as a “hit” or http operation
(httpop)
 Each line in the log file represents a hit
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Server Performance
 The size and type of files being transferred does not
necessarily slow a server
 The number of transactions over a network connection is
more important
 Factors that may slow a server include
 CGI programs and other applications
 Search engines
 Server-side programs accessing databases
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Resolving Server Performance Problems
 Some of the things needed to be done when a server is
struggling include:
 Increasing the server’s RAM
 Leads to increases cache to store frequently accessed data
 Upgrading the server configuration
 Faster hard drive to support sustained transfer rates
 Store data on multiple hard drives
 Distributing the load across different servers
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Web Server Platforms
(Operating Systems)
 Manages all the functions of a computer
 The choice of operating system is important for a
Web server because it determines:
 What server software to run
 The security and reliability of the Web server
 How the Web server can be managed
 Some of the operating system platforms include:
 Microsoft Windows, UNIX, Novell Netware, Apple Mac
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Windows
 By Microsoft Corporation
 The Windows platform has utilized several servers such
as:
 Windows NT Server
 Windows 2000 Server
 Windows Server 2003
 Windows Server 2008
 Windows Server 2008 R2
 Windows 8
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UNIX
 Created by AT&T Bell Laboratories
 Some popular brands of the UNIX platform include:
Linux (Ubuntu, Fedora, CentOS), Oracle Solaris, BSD
(FreeBSD, OpenBSD, NetBSD), IBM AIX, and HP-UX
 Basic components include:
 Kernel – central portion of operating system
 File system – provides input and output mechanisms
 Shell – provides user interface, e.g. sh, bash, csh

Popular GUIs include KDE, GNOME
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