Although many newer printers require a universal serial bus (USB) port, excellent support still exists for legacy parallel-port (IEEE-1284) printers with Linux, enabling sites to continue to use older hardware. You can take advantage of Linux workarounds to set up printing even if the host computer does not have a traditional parallel printer port or if you want to use a newer USB printer on an older computer.
For example, to host a parallel port-based printer on a USB-only computer, attach the printer to the computer using an inexpensive USB-to-parallel converter. USB-to-parallel converters typically provide a Centronics connector; one end of that connector is plugged in to the older printer, whereas the other end is plugged in to a USB connector. The USB connector is then plugged in to your hub, desktop, or notebook USB port. On the other hand, you can use an add-on PCI card to add USB support for printing (and other devices) if the legacy computer does not have a built-in USB port. Most PCI USB interface cards add at least two ports, and devices can be chained via a hub.
Related Fedora and Linux Commands
► accept — Controls print job access to the CUPS server via the command line
► cancel — Cancels a print job from the command line
► disable — Controls printing from the command line
► enable — Controls CUPS printers
► lp — Sends a specified file to the printer and allows control of the print service
► lpc — Displays the status of printers and print service at the console
► lpq — Views print queues (pending print jobs) at the console
► lprm — Removes print jobs from the print queue via the command line
► lpstat — Displays printer and server status
► system-config-printer — Displays Fedora's graphical printer configuration tool
► system-config-printer-tui — Displays Fedora's text-dialog printer configuration tool
Reference
► http://www.linuxprinting.org/ — Browse here for specific drivers and information about USB and other types of printers.
► http://www.hp.com/wwsolutions/linux/products/printing_imaging/index.html — Short but definitive information from HP regarding printing product support under Linux.
► http://www.cups.org/ — A comprehensive repository of CUPS software, including versions for Red Hat Linux.
► http://www.pwg.org/ipp/ — Home page for the Internet Printing Protocol standards.
► http://www.linuxprinting.org/cups-doc.html — Information about CUPS.
► http://www.cs.wisc.edu/~ghost/ — Home page for the Ghostscript interpreter.
► http://www.samba.org/ — Base entry point for getting more information about Samba and using the SMB protocol with Linux, UNIX, Mac OS, and other operating systems.
► In addition, an excellent book on Samba to help you learn more is Using Samba, 3rd Edition (O'Reilly & Associates, ISBN: 0-596-00769-8).
CHAPTER 20
Remote File Serving with FTP
File Transfer Protocol (FTP) was once considered the primary method used to transfer files over a network from computer to computer. FTP is still heavily used today, although many graphical FTP clients now supplement the original text-based interface command. As computers have evolved, so has FTP, and Fedora includes many ways with which to use a graphical interface to transfer files over FTP.
This chapter contains an overview of the available FTP soft ware included with Fedora, along with some details concerning initial setup, configuration, and use of FTP- specific clients. Fedora also includes an FTP server software package named vsftpd, the Very Secure FTP Daemon, and a number of associated programs you can use to serve and transfer files with the FTP protocol.
Choosing an FTP Server
FTP uses a client/server model. As a client, FTP accesses a server, and as a server, FTP provides access to files or storage. Just about every computer platform available has software written to enable a computer to act as an FTP server, but Fedora enables the average user to do this without paying hefty licensing fees and without regard for client usage limitations.
There are two types of FTP servers and access: standard and anonymous. A standard FTP server requires an account name and password from anyone trying to access the server. An anonymous server allows anyone to connect to the server to retrieve files. Anonymous servers provide the most flexibility, but they can also present a security risk. Fortunately, as you will read in this chapter, Fedora is set up to use proper file and directory permissions and common-sense default configurations, such as disallowing root from performing an FTP login.
Many Linux users now use OpenSSH and its suite of clients, such as the sftp command, for a more secure solution when transferring files. The OpenSSH suite provides the sshd daemon and enables encrypted remote logins (see Chapter 15 for more information).
Choosing an Authenticated or Anonymous Server
When you are preparing to set up your FTP server, you must first make the decision to install either the authenticated or anonymous service. Authenticated service requires the entry of a valid username and password for access. As previously mentioned, anonymous service allows the use of the username anonymous and an email address as a password for access.
Authenticated FTP servers provide some measure of secure data transfer for remote users, but require maintenance of user accounts as usernames and passwords are used. Anonymous FTP servers are used when user authentication is not needed or necessary, and can be helpful in providing an easily accessible platform for customer support or public distribution of documents, software, or other data.
If you use an anonymous FTP server in your home or business Linux system, it is vital that you properly install and configure it to retain a relatively secure environment. Sites that host anonymous FTP servers generally place them outside the firewall on a dedicated machine. The dedicated machine contains only the FTP server and should not contain data that cannot be restored quickly. This dedicated-machine setup prevents malicious users who compromise the server from obtaining critical or sensitive data. For an additional, but by no means more secure setup, the FTP portion of the file system can be mounted read-only from a separate hard drive partition or volume, or mounted from read-only media, such as CD-ROM, DVD, or other optical storage.
Fedora FTP Server Packages
The Very Secure vsftpd server, like wu-ftpd (also discussed in this chapter), is licensed under the GNU GPL. The server can be used for personal or business purposes. Other FTP servers are available for Fedora, but only vsftpd comes bundled with this book's DVD. The wu-ftpd and vsftpd servers are covered in the remainder of this chapter.