CITA 310 Section 8

Extending the Web Environment

(Textbook Chapter 9)

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

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

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

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

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

Understanding News Servers News servers allow threaded

discussions You post messages in a newsgroup A newsgroup focuses on a single topic There are hundreds of gigabytes of

information generated per day News servers can be set up for use

within an organization

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 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

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

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

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

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 HTTP, SMTP, POP3, and others

Broadcast methods unicast – each packet is sent individually to

each client multicast – each packet is sent to many

clients