ftpconversions file. Additional examples of conversion rules, such as for Sun's Solaris operating system, might be available in the wu-ftpd documentation.
Using ftphosts to Allow or Deny FTP Server Connection
The purpose of the ftphosts file is to allow or deny specific users or addresses from connecting to the FTP server. The format of the file is the word allow or deny, optionally followed by a username, followed by an IP or a DNS address.
allow username address
deny username address
Listing 20.3 shows a sample configuration of this file.
ftphosts Configuration File for Allowing or Denying Users# Example host access file
#
# Everything after a '#' is treated as comment,
# empty lines are ignored
allow tdc 128.0.0.1
allow tdc 192.168.101.*
allow tdc insanepenguin.net
allow tdc *.exodous.net
deny anonymous 201.*
deny anonymous *.pilot.net
The * is a wildcard that matches any combination of that address. For example, allow tdc *.exodous.net allows the user tdc to log in to the FTP server from any address that contains the domain name exodous.net. Similarly, the anonymous user is not allowed to access the FTP if he is coming from a 201 public class C IP address.
Changes made to your system's FTP server configuration files become active only after you restart xinetd because configuration files are parsed only at startup. To restart xinetd as root, issue the command /etc/rc.d/init.d/xinetd restart. This makes a call to the same shell script that is called at system startup and shutdown for any runlevel to start or stop the xinet daemon. xinetd should report its status as:
# /etc/rc.d/init.d/xinetd restart
Stopping xinetd: [ OK ]
Starting xinetd: [ OK ]
When the FTP server restarts, it is accessible to all incoming requests.
Using Commands for Server Administration
wu-ftp provides a few commands to aid in server administration. Those commands are:
> ftpwho — Displays information about current FTP server users
> ftpcount — Displays information about current server users by class
> ftpshut — Provides automated server shutdown and user notification
> ftprestart — Provides automated server restart and shutdown message removal
Each of these commands must be executed with superuser privileges because they reference the ftpaccess configuration file to obtain information about the FTP server.
Display Information About Connected Users
The ftpwho command provides information about the users currently connected to the FTP server. Here's the command line:
/usr/bin/ftpwho
Table 20.3 shows the format of the output ftpwho displays.
TABLE 20.3 ftpwho Fields
| Name | Description |
|---|---|
Process ID | The process ID of the FTP server process. |
TTY | The terminal ID of the process. This is always a question mark (? ) because the FTP daemon is not an interactive login. |
Status | The status of the FTP process. The values are: |
S: Sleeping | |
Z: Zombie, indicating a crash | |
R: Running | |
N: Normal process | |
Time | The elapsed processor time the process has used in minutes and |
