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Web Server Administration

Chapter 9Extending the Web

Environment

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Overview 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

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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

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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

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Communicating with FTPCommand 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

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Communicating with FTPCommand 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

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Communicating with FTPCommand Description Example

hash Displays a hash symbol as files are being downloaded

hash

cd directory Moves to another directory on the FTP server

cd /software

lcd directory Moves to another directory on the client

lcd /docs

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

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Install and Configure Windows FTP Server

Windows component Part of IIS

Configured through Internet Information Services (IIS) Manager

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Configure FTP Messages 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

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Install FTP in Linux

The wu-ftpd FTP server was developed by Washington University

Once the rpm is installed, enable FTP chkconfig wu-ftpd on Restart xinetd service to recognize

change service xinetd restart

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Configure /etc/ftpaccess 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 allow-uid ftp allow-gid ftp

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Configure /etc/ftpaccess

Limit user to a maximum of five failed logons before a disconnect loginfails 5

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

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Control Access

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

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

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Configure Messages To receive notice that a readme file exists at

login or any current working directory (cwd) readme README* login readme README* cwd=*

To display a message when a user logs on or moves to a directory

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

To create a banner message when client connects

banner /etc/banner.txt

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Understanding News Servers 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

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Configuring Telnet in Linux By default, telnet is installed but not enabled

chkconfig telnet on service xinetd restart

Telnet should not be used in a non-secure environment such as over the Internet because user names and passwords are not encrypted

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"

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Telnet and Windows Telnet is not popular in Windows because

telnet is text-based and Windows relies on a GUI 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 network-related items

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Common net CommandsCommand 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

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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 permissionsPermissions 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 Create a text file with commands to re-

create the IP configuration netsh interface ip dump

Ping the gateway IP address of each NIC netsh diag ping gateway

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

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Terminal Services in Windows GUI-based access to a server Can be used for remote administration

or running applications remotely 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

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Understanding Streaming Media Services Used to transfer video and audio By default, UDP is used

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 unicast – each packet is sent individually to

each client multicast – each packet is sent to many

clients

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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

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Understanding E-Commerce Servers 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

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Summary 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