File Transfer Protocol (FTP) is used only to transfer files from one computer to another. However, FTP isn't just for the Internet. You can also set up an FTP server on your local network to help users within your corporation find the information they need. Several versions of FTP clients are available, including both character-based and graphical-interface varieties. Software programs, such as Mosaic, can also provide a friendly client interface to the FTP server service.
The FTP server service is included with Windows NT and is documented in the TCP/IP book of your Windows NT Server documentation set. You can also review the information in the online Help file, TCPIP.HLP.
Note Before you install the FTP server service, read the following section, "Operating and Security Issues," for some tips on security and efficiency issues.
The hardware resources you require depend on the activity your FTP server handles and the kind of link you have to the Internet. For example, a Pentium-based computer with 48 MB of RAM can easily support 100 simultaneous FTP connections, if the link to the Internet can handle it.
For basic information on operating the FTP server service, see the TCP/IP book of your Windows NT Server documentation set, or the online Help file, TCPIP.HLP. This section provides some additional tips on operating a Windows NT FTP server on the Internet.
Since FTP requires users to explicitly log on to the computer where the files they are accessing are kept, it is best to keep all the material you want to share via FTP on one computer.
You can specify the directory that FTP clients will be in when they connect to your FTP server. The files you want to share can be organized into subdirectories of this directory, or, if there are relatively few files, you can just keep them all in the FTP directory itself.
You can also use Windows NT security to create one or more subdirectories to act as drop-boxes. Use the Security menu in File Manager to grant only Add privileges for the drop box directories to the public accounts (for example, Guest) that Internet users use to access your FTP server. Internet users can write to these directories, but cannot read or copy from them.
FTP passwords travel as clear text on the Internet. For this reason, many FTP server programs support anonymous (unsecured) FTP. If your users will be accessing a secure Windows NT computer acting as a FTP server from computers running any Microsoft networking software, and you want to use passwords, use the Windows NT Server service, which does encrypt passwords. The Internet user then connects to the Internet through any provider, and uses File Manager or the net use command to connect to your Internet server. The server prompts for a password and the client software encrypts and sends the password typed in by the user. With this method, you can grant different permissions to different usernames. However, users who are not using Windows NT client software cannot send the encrypted passwords. You might want to have them log on as anonymous.
FTP does not prevent users from changing directories from the initial FTP directory in which they were given access to parents of that directory. For example, if you specify d:\welcome as the initial FTP directory, the FTP users who connect to your FTP server can change to the root directory on d:, and to any of its subdirectories, if the permissions you have set on those directories let them do so. To protect the data you don't want to share with the public, either use NTFS and set protections on the root directory and other subdirectories for the logical drive you are using for the FTP directory, or (more simply) create a separate partition for FTP use. This is not an issue when you are using Gopher or World Wide Web (WWW) because these tools do not let users move up from the directory they initially connect to.