Introduction to FTP

In a Nutshell - CIW Course Section 3, Part B1, Chapter 8

FTP Overview

File Transfer Protocol is a standard, and an early, Internet protocol. It provides a simple method of transferring files from and to a server.

There are two basic FTP modes, Traditional and Passive. Nearly all modern FTP servers use the passive mode and this is considered to be the Firewall friendly mode. Many FTP clients will only work in passive mode. Microsoft IIS is the standard way to implement FTP on Windows 2000 as it is included with the installation disks.

There are 4 main types of Windows FTP server: IIS, WS_FTP, WAR_FTP and FTP-Serv-U.

FTP Commands

ls lists all files in the directory
cd changes directory
get downloads a file
put uploads a file
mget download multiple files
mput upload multiple files

Anonymous Access

Anonymous Access allows a user access to an FTP site without the need for a user account with the FTP server. Accessing the site from a web browser will not require any logon credentials but access from an FTP client will require the user to supply the username : anonymous and a password which is their email address. It is likely that anonymous users will have access to only a restricted area of the server and may not see all available files and folders. It is also likely that they will have read-only access to any directory.

Where a user account is to be supplied, access from a web browser will take the form of: ftp://username:password@hostname. If the server is a LInux server, then the root user may not access the FTP server in this manner. This is a restriction of the Linux Pluggable Authentication Module.

Managing FTP in IIS

FTP is part of IIS and is therefore managed from the IIS console. Right-click on the FTP site and select "Properties". The dialog box that is displayed has six tabs: FTP Site, Security Accounts, Messages, Home Directory and Directory Security.

The first tab is the FTP Site tab which allows the Site Name to be modified and the IP address to be selected. The IP address used must be a physical address on a NIC on the local machine.

The logging is worth a mention as there are three options available. Microsoft IIS Log File Format, ODBC Logging, and W3C Extended Log File Format. ODBC Logging allows you to specify a DSN to log events to a database, the other two log to text files which can be set in the "Properties"

From the Security Accounts tab the user account used by anonymous connections may be set as can the users deemed to be FTP operators. The Messages tab allows the "Welcome" and "Exit" messages to be set, these are displayed when a user connects to and disconnects from the server.

The Home Directory tab allows the location of the FTP directory to e set. This directory contains the file and folders available to FTP connected users.

The basic permissions of read and write may be set, and the listing style may also be changed. By default, the listing style is MS-DOS.