Web server administration chap09

Web Server Administration

Chapter 9
Extending the Web
Environment
1


Overview
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Understand File Transfer Protocol (FTP)
services
Install and configure an FTP server in
Windows
Install and configure an FTP server in Linux
Understand News servers
Configure remote access to a server
Understand streaming media servers
Understand e-commerce software
2

Understanding FTP
Services




FTP is used to transfer files from a server
to a client (download) and transfer files
from a client to a server (upload)
FTP client is the browser




Also command-line and GUI clients

FTP servers can operate as anonymous
servers or they can require a valid logon



Typically, they are anonymous
FTP servers are not secure; user names and
passwords are not sent encrypted
3


Understanding FTP
Services






The client connects to port 21
(control port)
Port 20 (data port) is used to tell
the client which unprivileged port
to use for data transfer
The above describes passive mode
FTP, the most common type
4


Communicating with FTP
Command

Description

Example

ftp host

Initiates a connection to FTP server

ftp 192.168.0.100

open host

Once the FTP client has been started,
opens a connection

open 192.168.0.100

close

Closes the connection but does not
exit the FTP client

close

quit or
bye

Closes the connection and exits the
FTP client

bye

ls
filenames

Displays filenames and can use
wildcards

ls *.rpm

dir
filenames

Displays the long listing of files and
their properties, such as the size and
date the file was created

dir *.rpm

5


Communicating with FTP
Command

Description

Example

binary

Transfer files in binary mode

binary

ascii

Transfer files in text mode

ascii

get filename

Downloads a single file

get test.rpm

put filename

Uploads a single file

put testapp.zip

Mget filenames Downloads multiple files;
used with wildcards

mget sendmail*.rpm

mput filenames Uploads multiple files;
used with wildcards

mput *.tif

prompt no

Stops prompting for each file
when used before you use
mget or mput

prompt no

prompt

Starts prompting

prompt
6


Communicating with FTP
Command

Description

Example

hash

Displays a hash symbol as files
are being downloaded

hash

cd directory

Moves to another directory on the cd /software
FTP server

lcd directory

Moves to another directory on the lcd /docs
client

pwd

Displays the current directory on
the server

pwd

help command

Finds very brief help on FTP
commands; if used without a
reference to a command, it
will give you a list of
commands available

help mget

7


Install and Configure
Windows FTP Server


Windows
component
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Part of IIS

Configured
through
Internet
Information
Services (IIS)
Manager
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Configure FTP Messages
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Banner appears
when client connects
Welcome appears
when logged on
Exit appears when
client exits from
server
Maximum
connections appears

when limit is
reached and client
cannot connect
9


Install FTP in Linux


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The wu-ftpd FTP server was
developed by Washington University
Once the rpm is installed, enable FTP
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chkconfig wu-ftpd on
Restart xinetd service to recognize
change
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service xinetd restart

10


Configure /etc/ftpaccess
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The /etc/ftpaccess file is the main
configuration file
By default, users with IDs less than
or equal to 99 are not allowed



They are for system users and daemons
Because the ftp user is a system user,
you have to allow it with

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allow-uid ftp
allow-gid ftp
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Configure /etc/ftpaccess
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Limit user to a maximum of five
failed logons before a disconnect
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loginfails 5

Check for password that conforms
to e-mail address
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passwd-check rfc822 warn

12


Control Access
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Set up user classes
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class all real,guest,anonymous *
class local real 192.168.0.0/24

Set limits for class
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file-limit out 25 anonymous
file-limit in 10 local
byte-limit out 2000000 anonymous

13


Configure Messages
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To receive notice that a readme file exists at
login or any current working directory (cwd)
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To display a message when a user logs on or
moves to a directory
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readme README* login
readme README* cwd=*

message /welcome.msg login
message .message cwd=*

To create a banner message when client
connects
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banner /etc/banner.txt
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Understanding News
Servers
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News servers allow threaded discussions
You post messages in a newsgroup
A newsgroup focuses on a single topic
There are more than 40,000 public
newsgroups
There are hundreds of gigabytes of
information generated per day
News servers can be set up for use
within an organization
15


Configuring Telnet in Linux


By default, telnet is installed but not enabled



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Telnet should not be used in a non-secure
environment such as over the Internet because
user names and passwords are not encrypted
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chkconfig telnet on
service xinetd restart

ssh is a secure replacement (described in Chapter
10)

You cannot log on as root


However, you can log on as another user and "su
root"
16


Telnet and Windows


Telnet is not popular in Windows because
telnet is text-based and Windows relies on a
GUI
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However, there are many command-line utilities
that can be used, especially in Windows Server
2003

Before Windows, Microsoft networking
depended on a single command net with
many options
cacls can be used to alter permissions
netsh starts a networking shell which allows
you to configure and display many networkrelated items
17


Common net Commands
Command

Description

Example

net user

Lists all users

net user

net user username

Displays user
information

net user mnoia

net start service

Starts a service

net start "FTP Publishing
Service"

net share
name=location

Shares a folder

net share docs=c:\docs

net use drive:
\\computer\share

Maps a drive

net use g: \\web1\docs

18


cacls options


The format is: cacls file or folder name [options]

Option

Description

/e

Changes instead of replaces permission

/t

Changes all subfolders

/g user:perm

Grants a user specific permissions
Permissions are:
f (full control)
r (read)

w (write)
c (change)
n (none)

/p user:perm

As above, except permissions are replaced

/r user /e

Revokes permission

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netsh Examples
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Create a text file with commands to recreate the IP configuration
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Ping the gateway IP address of each NIC
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netsh interface ip dump
netsh diag ping gateway

In Windows Server 2003
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Display errors in system log
Manage network monitor and performance
Defragment a drive
Shut down a server
20


Terminal Services in
Windows
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GUI-based access to a server
Can be used for remote administration
or running applications remotely
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In Windows 2000, you select remote
administration on installation
In Windows Server 2003, it is installed
already and you have to enable it

Client software is included in Windows
Server 2003 and Windows XP
You have to install client software for
Windows 2000
21


Understanding Streaming
Media Services
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Used to transfer video and audio
By default, UDP is used
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Although TCP and HTTP can be used
because of firewall issues in an organization

No single standard exists as is true with
SMTP, HTTP, POP3, and others

Broadcast methods
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unicast – each packet is sent individually to
each client
multicast – each packet is sent to many
clients
22


Understanding Streaming
Media Services


Helix Universal Server from Real
Networks is popular




Recognizes both Real Networks
protocols (RTSP, PNA) and the Microsoft
protocol (MMS)

Windows Media Services is a
Windows component


Creates a folder called \ASFRoot to store
Advanced Streaming Format (ASF) files
23


Understanding ECommerce Servers
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Can be as simple as a product list and a
shopping cart
Can be as complex as amazon.com or
dell.com
Microsoft Commerce Server is an add-on
to IIS




Incorporates a number of features required
for a typical e-commerce site
Highly customizable
24


Summary
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Use FTP to transfer files
You use News servers to set up threaded
discussions on a variety of topics
Telnet and Windows Terminal Services
allow you to remotely administer a server
Streaming media servers are used for
video and audio
E-commerce servers focus on selling and
in general, communicating with customers
25