| seconds. | |
Details | Tells from what host the process is connecting, the user who connected, and the currently executing command. |
Listing 20.4 shows typical output from this command. It lists the process ID for the ftp daemon handling requests, the class to which the particular user belongs, the total time connected, the connected username, and the status of the session.
In addition to the information given about each connected user, ftpwho also displays the total number of users connected out of any maximum that has been set in the ftpaccess file. This information can be used to monitor the use of your FTP server.
You can pass one parameter to ftpwho. (You can find the parameter by using the ftpwho --help command.) The single parameter you can pass to ftpwho is -V. This parameter prints out version and licensing information for wu-ftp, as shown here:
# ftpwho
Service class all:
10447 ? SN 0:00 ftpd: localhost: anonymous/[email protected]: IDLE
1 users (no maximum)
The output of ftpwho, using the -V option, which shows version information, is shown in Listing 20.4.
ftpwho -V Command OutputCopyright © 1999,2000,2001 WU-FTPD Development Group.
All rights reserved.
Portions Copyright © 1980, 1985, 1988, 1989, 1990, 1991, 1993, 1994
The Regents of the University of California.
Portions Copyright © 1993, 1994 Washington University in Saint Louis.
Portions Copyright © 1996, 1998 Berkeley Software Design, Inc.
Portions Copyright © 1989 Massachusetts Institute of Technology.
Portions Copyright © 1998 Sendmail, Inc.
Portions Copyright © 1983, 1995, 1996, 1997 Eric P. Allman.
Portions Copyright © 1997 by Stan Barber.
Portions Copyright © 1997 by Kent Landfield.
Portions Copyright © 1991, 1992, 1993, 1994, 1995, 1996, 1997
Free Software Foundation, Inc.
Use and distribution of this software and its source code are governed by
the terms and conditions of the WU-FTPD Software License ('LICENSE').
If you did not receive a copy of the license, it may be obtained online
at http://www.wu-ftpd.org/license.html.
Version wu-2.6.2-8
Count the Number of Connections
/usr/bin/ftpcount counts the number of connected users to the FTP server and the maximum number of users allowed. This same information is found at the end of the output for the ftpwho command. This command takes only one parameter, -V, which displays the same output as the previous ftpwho example.
# ftpcount
Service class all - 4 users (no maximum)
Use /usr/sbin/ftpshut to Schedule FTP Server Downtime
As with any public server administration, it is always good practice to let users of the FTP server know about upcoming outages, when the server will be updated, and other relevant site information. The ftpshut command allows the administrator to let the FTP server do much of this automatically.
The ftpshut command enables the administrator to take down the FTP server at a specific time, based on some parameters passed to it. The format of the command is as follows and is documented in the ftpshut man page:
ftpshut [ -V ] [ -l min] [ -d min] time [ warning-message ... ]
The -V parameter displays the command's version information. The time parameter is the time when the ftpshut command will stop the FTP servers. This parameter takes either a + number for the number of minutes from the current time, or a specific hour and minute in 24-hour clock format with the syntax of
The -l parameter enables the FTP server administrator to specify how long, in minutes, before shutdown the server disallows new connections. The default is 10 minutes. If the time given to shut down the servers is less than 10 minutes, new connections are disallowed immediately.
The -d parameter is similar to the -l parameter, but controls when the FTP server terminates the current connections. By default, this occurs five minutes before the server shuts down. If the shutdown time is less than five minutes, the server terminates the current connections immediately.
When you execute this command, the FTP server creates a file containing the shutdown information in the location specified under the shutdown section in the ftpaccess file. The default configuration for this file is /etc/shutmsg. If you execute the ftpshut command with warning messages, the messages are displayed when the user logs in to the server.
Name (pheniox:tdc): anonymous
331 Guest login ok, send your complete e-mail address as password.
Password:
230-system doing down at Mon Sep 3 06:23:00 2001
230-0 users of unlimited on pheniox.
230 Guest login ok, access restrictions apply.
Remote system type is UNIX.
Using binary mode to transfer files.
Here is a sample ftpshut command:
ftpshut -l 5 -d 5 +10 'system going down at %s %N users of %M on %R'
This command tells the FTP server to disconnect new connections in 5 minutes, drop all current connections in 5 minutes, shut down the server in 10 minutes, and display a warning message to the users at login. The message can be a mixture of text and the magic cookies defined in Table 20.4. It is important to keep in mind that the message can be a maximum of 75 characters in length. Additionally, it is not important to know how many characters the magic cookies take because the system knows this information and truncates the message at 75
