Provides the server function for the Internet FTP protocol.
Note: The ftpd daemon is normally started by the inetd daemon. It can also be controlled from the command line, using SRC commands.
/usr/sbin/ftpd [ -d ] [ -k ] [ -l ] [ -t TimeOut ] [ -T MaxTimeOut ] [ -s ] [ -u OctalVal ]
The /usr/sbin/ftpd daemon is the DARPA Internet File Transfer Protocol (FTP) server process. The ftpd daemon uses the Transmission Control Protocol (TCP) to listen at the port specified with the ftp command service specification in the /etc/services fil.
Changes to the ftpd daemon can be made using the System Management Interface Tool (SMIT) or System Resource Controller (SRC), by editing the /etc/inetd.conf or /etc/services file. Entering ftp at the command line is not recommended. The ftpd daemon is started by default when it is uncommented in the /etc/inetd.conf file.
The inetd daemon gets its information from the /etc/inetd.conf file and the /etc/services file.
If you change the /etc/inetd.conf or /etc/services file, run the refresh -s inetd or kill -1 InetdPID command to inform the inetd daemon of the changes to its configuration files.
The ftpd daemon expands file names according to the conventions of the csh command. This command allows you to use such metacharacters as the * (asterisk), the ? (question mark), [ ] (left and right brackets), { } (left and right braces), and the ~ (tilde).
Before the ftpd daemon can transfer files for a client process, it must authenticate the client process. The ftpd daemon authenticates client processes according to these rules:
The ftpd daemon allows access only if all of the following conditions are satisfied:
When handling an anonymous FTP user, the server performs the chroot command in the home directory of the FTP user account. For greater security, implement the following rules when you construct the FTP subtree:
Note: The shell script /usr/samples/tcpip/anon.ftp uses the above rules to set up the anonymous FTP account for you.
The server must run as the root user to create sockets with privileged port numbers. The server maintains an effective user ID of the logged-in user, reverting to the root user only when binding addresses to sockets.
The ftpd daemon currently supports the following FTP requests:
The remaining FTP requests defined in Internet RFC 959 are recognized, but not implemented. The MDTM and SIZE requests are not specified by RFC 959, but are scheduled to appear in the next updated FTP RFC.
If a STAT request is received during a data transfer and preceded by both a Telnet IP signal and SYNCH signal, transfer status is returned.
The ftpd daemon should be controlled using the System Management Interface Tool (SMIT) or by changing the /etc/inetd.conf file. Entering ftpd at the command line is not recommended.
The ftpd daemon is a subserver of the inetd daemon, which is a subsystem of the System Resource Controller (SRC). The ftpd daemon is a member of the tcpip SRC subsystem group. This daemon is enabled by default in the /etc/inetd.conf file and can be manipulated by the following SRC commands:
startsrc | Starts a subsystem, group of subsystems, or a subserver. |
stopsrc | Stops a subsystem, group of subsystems, or a subserver. |
lssrc | Gets the status of a subsystem, group of subsystems, or a subserver. |
-d | Sends debugging information about ftpd daemon operations
to the syslogd
daemon. If you specify the -d flag, you must edit
the /etc/syslog.conf file and add the following entry:
daemon.debug FileName Note: The syslogd daemon's debug level includes info level messages. If you do not edit the /etc/syslog.conf file, no messages are produced. After changing the /etc/syslog.conf file, run the refresh -s syslogd command or kill -1 SyslogdPID command to inform the syslogd daemon of the changes to its configuration file. For more information about debug levels, refer to the /etc/syslog.conf file. |
-k | Sets the SO_KEEPALIVE option defined in the sys/socket.h file on the data transfer socket to enable the data transfer to time out in the event TCP/IP hangs. The idle interval time is based on systemwide values designated by the tcp_keepidle and tcp_keepintvl options of the no command. Without the flag, ftpd data transfer will not time out. |
-l | Sends logging information about ftpd daemon operations to the syslogd daemon. If you specify the -l flag, you must edit the /etc/syslog.conf file and add the following entry:
daemon.info FileName If you do not edit the /etc/syslog.conf file, no messages are produced. After changing the /etc/syslog.conf file, run the refresh -s syslogd command or kill -1 SyslogdPID command to inform the syslogd daemon of the changes to its configuration file. For more information about debug levels, refer to the /etc/syslog.conf file. |
-t TimeOut | Logs out inactive sessions after the number of seconds specified by the TimeOut variable. The default limit is 15 minutes (900 seconds). |
-T MaxTimeOut | Logs out inactive client sessions after a maximum number of seconds specified by the MaxTimeOut variable. The default limit is 2 hours (7200 seconds). |
-s | Turns on socket-level debugging. |
-u OctalVal | Sets the ftpd daemon's umask. The OctalVal variable must be specified as an octal value to define the umask. The default umask is an octal value of 027, which results in file permissions of rw-r-----. |
Note: The arguments for the ftpd daemon can be specified by using SMIT or by editing the /etc/inetd.conf file.
startsrc -t ftpThe startsrc command with the -t flag starts the ftpd subserver. You must use the -t flag to specify a subserver. Otherwise, the command does not execute properly.
stopsrc -t ftpThe stopsrc command with the -t flag stops the ftpd subserver. The stopsrc command allows all pending connections to start and all existing connections to complete, but prevents new connections from starting. You must use the -t flag to specify a subserver. Otherwise, the command does not execute properly.
stopsrc -t -f ftpThe stopsrc command with the -t and -f flags forces the ftpd subserver to stop. It terminates all pending connections and existing connections immediately.
lssrc -t ftpThe lssrc command with the -t flag returns the daemon's name, process ID, and state (active or inactive). You must use the -t flag to specify a subserver. Otherwise, the command does not execute properly.
/etc/locks/ftpd | Contains interlock and process ID (PID) storage. |
/etc/group | Contains passwords for groups. |
/etc/passwd | Contains passwords for users. |
/etc/security/login.cfg | Contains configuration information for login and user authentication. |
/etc/security/passwd | Contains encrypted passwords. |
/etc/syslog.conf | Contains configuration information for the syslogd daemon. |
/usr/samples/tcpip/anon.ftp | Contains the example shell script with which to set up an anonymous FTP account. This file also contains directions for its use. |
The ftp command, lssrc command, kill command, no command, rcp command, refresh command, rlogin command, rsh command, startsrc command, stopsrc command, telnet command.
The inetd daemon, syslogd daemon.
The kvalid_user function.
The /etc/ftpusers file format, /etc/inetd.conf file format, /etc/services, $HOME/.k5login file format.
TCP/IP Daemons in AIX Version 4.3 System Management Guide: Communications and Networks.
Secure Rcmds in AIX Version 4.3 System User's Guide: Communications and Networks.