FTP (File Transfer Protocol)

FTP is an means of copying Internet files to and from servers using TCP/IP protocols.

URLs:

FTP List

The Anonymous FTP Sitelist and FAQ maintained by Perry Rovers.

RFC 542: File Transfer Protocol for the ARPA Network

The official description of the FTP protocol.

RFC 1635: How To Use Anonymous FTP

Information for the novice on what FTP is and how to use it--including transcripts of anonymous FTP sessions.

W3E References:

Netiquette

Users of FTP are admonished to observe rules of network etiquette when accessing files from remote computers.

Anonymous FTP

Anonymous FTP is a special case of file transfer protocol in which an archive site grants essentially unrestricted public access to specific files.

Archie

To download a file, you must first know where to find it. The Archie program provides a database of files that are available via anonymous ftp.

Print References:

• Using Ftp by Mary Ann Pike. Que. Indianapolis, IN. 1995. (ISBN: 0-78-97023-8X)
• All About Internet Ftp : Learning and Teaching to Transfer Files on the Internet (Internet Workshop Series ; Volume 2) by David F. Robinson. Library Solutions Institution and Press. 1994. (ISBN: 1-88-22080-48)

Detail:

Background

The Internet offers access to archives of software, government documents, games, and literature--as well as to documents on the use of the Internet--at thousands of sites. Files can be accessed via file transfer protocol, or ftp.

The original specifications for ftp site four objectives:

• to promote sharing of files (computer programs and/or data)
• to encourage the use of remote computers
• to shield users from variations in host file storage systems
• to transfer data reliably and efficiently

File transfer can be initiated by user commands or by other programs.

Using Ftp

Most systems have direct access to ftp. If yours does not, you can access ftp via telnet or e-mail.

In general, all ftp sessions involve the following steps:

• Log on to your local host.
• Open a connection to an ftp host by typing the command: "ftp hostname".
• Log in with an appropriate username and provide the necessary password.
• Issue commands to change directories or to retrieve a file.
• When finished, exit the FTP program, thereby closing your connection to the remote host.

Text-interface programs require specific commands for each step of the process. With graphic-interface programs, clicking on an icon issues the desired command(s).

FTP Commands

Some useful commands available on most systems include:

• ASCII --Switch to ASCII mode. ASCII mode is the default mode used for transferring text files
• binary-- Switch to binary mode, for transferring binary files such as .ZIP or .Z files
• cd-- Change the directory on the remote computer
• dir-- List the files in the current directory on the remote computer
• ls-- Same as 'dir', but can show less information
• get--- Copy a file from the remote computer to yours
• hash-- Put a '#' on the screen for every <number> of bytes transferred. <number> is between 1024 and 4096 in most cases.
• help-- Get help on the use of commands within the ftp program
• lcd-- Change the directory on your computer (the 'l' is for local)
• lpwd-- Show the present working directory (pwd) on your computer
• mget-- Copy multiple files from the remote computer to yours
• pwd-- Show the present working directory (pwd) on the remote computer

For full details on commands and options, type "help" at the ftp prompt or "man ftp" at a UNIX prompt.

Special File Formats

Information stored on archive sites is often transformed in one or more ways.

• Compression reduces the size of files for easier storage and/or more rapid transfer.
• Archiving or bundling combines several files into one to simplify transfer.
• Encoding of 8-bit "binary" data into printable 7-bit ASCII format allows it to be transmitted via ftp.

Files must be decompressed, unarchived, or decoded with separate programs after transfer.

With dial-up terminal access files are FTPed to your local host, then downloaded to your PC using Xmodem, Zmodem, Kermit or some other communications protocol--a two-step process.

Anonymous FTP Sites

Thousands of anonymous FTP sites offer public access to certain files-- generally within a ".pub" subdirectory. For a comprehensive alphabetic listing of Internet sites accepting Anonymous FTP, send an e-mail message with no subject and in the body: send usenet/news.answers/ftp-list/sitelist/part# [where # is a number from 1 to 21] to mail-server@rtfm.mit.edu.