The University of AkronSummit College

Business Technology Dept.2440: 141

Web Site Administration

Remote Web Server Access ToolsInstructor: Enoch E. Damson

Web Environment ServersSome servers you can access remotely include:

File Transfer Protocol (FTP) serversNetwork News Transfer Protocol (NNTP) serversTelnetStreaming Media Servers

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Running An FTP ServerFile Transfer Protocol (FTP)

Used to shares files between networked computersClient and server programs available for all platforms

FTP has been integrated into modern Web browsersAnonymous FTP

Current primary use of FTPAllows access to FTP server without account

FTP servers may be set up to restrict file accessUsers authorized to access files are "known"

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FTP Client/Server InteractionsFTP utilizes two ports:

Control port (port 21) – serves as a communication channel between the client and the server for commands/replies exchange

Data port (port 20) – used purely for the data exchangeFTP can operate in two modes:

Active FTP – the FTP client does not make actual data connection to the server The client informs the server of its own port with a port command

Passive FTP – the FTP client issues a pasv command to indicate that it wants to access data in passive mode

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Using an FTP ClientRequired for accessing an FTP serverFTP clients may be text-based or graphicalAccessing an anonymous FTP server with ftp

Specify the server name after the ftp command Example: ftp ftp.ibiblio.org

A username and password may be needed Enter anonymous as username Enter e-mail address as a password

Following logon, ftp> prompt appears Enter commands to interact with the FTP server Enter bye to exit

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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 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.zip

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 FTP…Command 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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Using an FTP Client…Using a Web browser to access FTP sites

Point browser to ftp server Example: ftp://ftp.hq.nasa.gov

Browser logs on to FTP server Uses anonymous as username Uses e-mail address as password

Browser creates HTML pages and file listings on the flyManipulate displayed files using mouse

Logging on to an FTP server with a user accountProvides greater access to features of FTP serviceFTP administrator may still restrict activities

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Using an FTP Client…There are several FTP clients availableOne of the clients installed on the Fedora core is:

gFTP: FTP specific graphical client

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FTP ServersSome FTP servers include:

vsftpd (very secured ftp daemon)wu-ftp: Washington University FTP server

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FTP Servers…Three types of FTP users

Anonymous: use ftp or anonymous as logon nameReal: use a regular Linux user account Guest: use restricted regular user accounts

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Setting Up FTP Configuration Files…Define user classes to assign permissions by groupExample of class including all three FTP user types

class office real, guest, anonymous 192.168.100.0/24 All users logging on from given address are in office

Define message files for screen displayContents automatically displayed by FTP server

Controlling file actions permitted to FTP userUse series of directives naming file actionFollow directive with yes or no Include class of user to which directive applies

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Understanding News ServersNews servers allow threaded discussions You post messages in a newsgroupA newsgroup focuses on a single topicThere are several public newsgroups availableThere are hundreds of gigabytes of information

generated per dayNews servers can be set up for use within an

organization

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Telnet and WindowsTelnet is not popular in Windows because telnet is

text-based and Windows relies on a GUIHowever, there are many command-line utilities that can

be usedBefore Windows, Microsoft networking depended

on a single command net with many optionscacls can be used to alter permissionsnetsh starts a networking shell which allows you to

configure and display many network-related items

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Understanding Streaming Media ServicesUsed to transfer video and audioBy default, UDP is used

Although TCP and HTTP can be used because of firewall issues in an organization

No single standard existsBroadcast methods

unicast – each packet is sent individually to each clientmulticast – each packet is sent to many clients

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Understanding E-Commerce ServersCan be as simple as a product list and a shopping cartCan be as complex as amazon.comMicrosoft 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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