FTP (File Transfer Protocol) allows you to exchange files over the Internet. FTP consists of 2 programs.

1. An FTP client software which you would normally use.
2. An FTP server which stores and manages files.

FTP is most commonly used to download files from the FTP server. FTP is also used to upload/save files to the FTP Server.

The FTP protocol is a well known standard. FTP servers and clients adhere to this Standard. This makes the variations in file storage systems among hosts, transparent to the end user. FTP servers can be located on Unix, Windows, VMS, MVS, OS2 etc.. but the end user is shielded from these settings.

To transfer files via FTP you need to have an FTP Software installed on your computer. This client software allows you to connect to an FTP server and download and upload files from or to the server.

An FTP server allows users to access folders and files within its system. Some sites allow anyone to log on anonymously and access files in their public directory. Most sites require users to obtain a username and password to access their FTP site.

Once you log on to an FTP server, you will see your FTP home folder. You will have access to all files and sub directories in this home folder. Other users who have an account to this FTP server cannot access any files or directories in your home folder.

Directory paths

The FTP directory paths follow the Unix format. The root folder is typically /. When you log on to your FTP server using any FTP client, you will initially see your home folder. Examples of home folder paths (if your FTP username is bob):

/users/bob/
/home/users/bob/
/bob/

ASCII vs. Binary

FTP transfers are generally performed in either ASCII or binary mode. Binary mode is the preferred mode to transfer non-text files. ASCII mode is the preferred mode to transfer text files.

Active vs. Passive

This concept is useful if the FTP client computer or the FTP server system are protected by firewalls. If your computer is protected by a firewall, then passive mode is recommended.

Secure FTP

The FTP protocol is not secure. If someone intercepts the data during transfer between client and server, they can see the username / password and the other data transferred. Hence many companies now require their employees to only use secure FTP protocol.

There are two different FTP protocols, FTPs and SFTP. FTPs is the regular FTP protocol wrapped up in SSL. SFTP is a completely different protocol. SFTP is built on SSH2 (secure shell) protocol which is commonly in-built into most Unix systems.