Ubuntu Unleashed, Second Edition

Configuring the Wu-FTPd Server

Wu-FTP uses a number of configuration files to control how it operates, including the

following:

.

ftpaccess—Contains the majority of server configuration settings

. ftpconversions—Contains definitions of file conversions during transfers

. ftphosts—Settings to control user access from specific hosts

These files may be created in the /etc directory during installation, or may be created by

a system administrator. The following sections describe each of these files and how to use

the commands they contain to configure the Wu-FTP server is accessible to all incoming

requests.

CAUTION

When configuring an anonymous FTP server, it is extremely important to ensure that all

security precautions are taken to prevent malicious users from gaining privileged level

access to the server. Although this chapter shows you how to configure your FTP

server for secure use, all machines connected to the Internet are potential targets for

malicious attacks. Vulnerable systems can be a source of potential liability, especially

if anyone accesses and uses them to store illegal copies of proprietary software—

even temporarily.

TIP

Whenever editing the FTP server files, make a backup file first. Also, it is always a

good idea to comment out (using a pound sign at the beginning of a line) what is

changed instead of deleting or overwriting entries. Follow these comments with a brief

description why the change was made. This leaves a nice audit trail of what was done,

by whom, when, and why. If you have any problems with the configuration, these

comments and details will help you troubleshoot and return to valid entries if neces-

sary. You can use the

dpkg command or other Linux tools (such as mc) to extract a

fresh copy of a configuration file from the software’s package archive. Be aware,

however, that the extracted version will replace the current version and overwrite your

configuration changes.

NOTE

Back up the FTP server configuration files to another machine, should any of the

working copies become corrupt. There might be a need to replicate server configura-

tions across multiple hosts or revert back to an original copy of the defaults at some

point in time. By making regular backups before changing a file, you guarantee that the

changes can be undone and a working server restored with minimal down time.

Configuring the Wu-FTPd Server

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