What Is FTP And How It Works?
FTP is a method to manage files over the Internet or a
network: meet the File Transfer
Protocol!
People are generally using the FTP for transfering the files
uploaded on their web hosting server. We already talking about
files... trasfer, and most important... protocols.
A protocol is a method which informs your computer about the
connection to a server or client (in a nut shell, tells the
browser how to get the file, how to read the informations about
it, etc).
The FTP is a common process used in file trasfers from
one computer to another: one computer is the server and the
other one is being called - the client (because it connects to
the server).
A server is uploading when sending files, and the client is
downloading them. These are commonly used terms and I believe
you have heard about them before.
To access a FTP server you need an internet or network
connection, a FTP address, a username and a password.
The FTP address of the server is the main thing you must know
before accessing a server. Here is an example: a friend of mine
put some files on his computer and gave me the adress which
looks like this: ftp.myfriendsdomain.com
To access this address, i can use my browser (e.g. Firefox,
Internet Explorer, etc), or a FTP Client (a software for
connecting to FTP servers).
It's possible the server to be password protected, or I will
connect anonymously using my email address as a password.
Connecting anonymously?
That's right! If the server is granting acess to everybody, you
will connect anonymously - using anonymous word as username and
your email address as password. But this happens only when you
are allowed to connect anonymously.
In many cases privacy is king. For this reason, the anonymous
connection mode is disabled. You will need a username and
password to establish a connection to that server. The method is
used for protecting different areas on the server.
Clients and browsers?
There is a big difference from connecting to a FTP server using
a browser or a client. In most cases the browser will allow to
connect and download files from a server.
On the other hand, if you are using a FTP client you can:
download, upload, delete files, etc.
FTP vs. HTTP
Accessing a server using the HTTP (Hyper Text Trasfer
Protocol) is commonly used for websites. If you will access
www.cnn.com
with your browser, you got yourself a quick HTTP connection.
Let me show you two major differences between FTP and HTTP:
1) When connecting to a FTP server you are using a FILE server
(that means you can't see anything but files there), but if you
connect to a HTTP server you access a WEB server, which means
you can load web pages into a browser.
2) Using a FTP connection you can download and upload files to
the server, but when you use the HTTP connection you can only
download content from the Internet for viewing, is a "read only"
method.
Another thing you can do with the FTP method is to change mode
of the files. Why? Because you might use certain files that need
different permissions.
For example I have a small web application which stores your
name and email address inside a file on the server. If that file
is write protected, I can't store any information. I need to
change it's writing permission. This step is also called
chmod-ing a file.
What is CHMOD?
The chmod command is used to change permissions of a file
using the File Trasfer Protocol.
After you've uploaded something on a server you might want to
set up the file permissions. For example: the owner can change
the file's content, but any visitor comming here can only read
it.
This is done using 3 simple commands: write, read, execute.
Every command can be assigned (in the same time or dispersed)
for owner, groups and anyone else.
Sometimes the chmod commands are hard to use and understand, but
now it's easier, thanks to the three digit numbers!
Here are the most used commands for chmod-ing a file:
CHMOD 644 The file can be read by: owner, groups and
everyone else, but can't be changed, or executed but other
people excepting the owner.
CHMOD 700 The file can be read, written and excuted by
the owner (user). The groups and everyone else can't read, write
or execute it.
CHMOD 755 The owner, the group and everyone else can read
and execute the file, but only the owner can write it. (this is
a very common option for chmoding a file because allows the
execution of a file - it's valuable for web applications).
CHMOD 777 Full access to everyone for reading, executing
or writing the data.
Fact: FTP is used mostly for uploading files to a web
hosting server! Webmasters are using this procedure to put
websites online for their visitors.
Free FTP Clients (some of them are free only for personal
use):
-WS_FTP
-AutoFTP
-FTP Explorer
-FTP Works
-SmartFTP
Best wishes,
Vladimir Ghetau