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CentOS / Red Hat Linux Install VSFTPD FTP Server

Q. How do I configure and install an FTP server in CentOS / RHEL 5 / Fedora Linux server?
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How To Tell If Your Linux Server Uses xinetd OR inetd sever

Q. How to tell if my Linux server is using xinetd or inetd service?
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Linux / UNIX killing a process and restarting the same

Q. How do I kill a process called inetd or foo and restart the same so that configuration file get updated?

A. Both UNIX and Linux supports POSIX reliable signals and POSIX real-time signals. Each signal has a current disposition, which determines how the process behaves when it is delivered the signal.

Generally following command is used
kill -1 process-pid

First get pid of inetd:
ps -e | grep inetd
Now force read inetd.conf:
kill -1 xinetd-pid

You can also use pkill command used to send signals. The pkill command allows the use of extended regular expression patterns and other matching criteria.
pkill -HUP process-name

Make syslog reread its configuration file
# pkill -HUP syslogd

Make xinetd reread its configuration file
# pkill -HUP inetd

Howto: configure xinetd service under Linux or UNIX systems

Q. How do I configure xinetd under Fedora Core Linux?

A. xinetd, the eXtended InterNET Daemon, is an open-source daemon which runs on many Linux and Unix systems and manages Internet-based connectivity. It offers a more secure extension to or version of inetd, the Internet daemon.

xinetd performs the same function as inetd: it starts programs that provide Internet services. Instead of having such servers started at system initialization time, and be dormant until a connection request arrives, xinetd is he only daemon process started and it listens on all service ports for the services listed in its configuration file. When a request comes in, xinetd starts the appropriate server. Because of the way it operates, xinetd (as well as inetd) is also referred to as a super-server.

Task: xinetd Configuration files location

Following are important configuration files for xinetd:

  • /etc/xinetd.conf - The global xinetd configuration file.
  • /etc/xinetd.d/ directory - The directory containing all service-specific files such as ftp

Task: Understanding default configuration file

You can view default configuration file with less or cat command:
# less /etc/xinetd.confOR# cat /etc/xinetd.confOutput:

# Simple configuration file for xinetd
# Some defaults, and include /etc/xinetd.d/
        instances               = 60
        log_type                = SYSLOG authpriv
        log_on_success          = HOST PID
        log_on_failure          = HOST
        cps                     = 25 30
includedir /etc/xinetd.d


  • instances = 60 : Determines the number of servers that can be simultaneously active for a service. So 60 is the maximum number of requests xinetd can handle at once.
  • log_type = SYSLOG authpriv: Determines where the service log output is sent. You can send it to SYSLOG at the specified facility (authpriv will send log to /var/log/secure file).
  • log_on_success = HOST PID: Force xinetd to log if the connection is successful. It will log HOST name and Process ID to /var/log/secure file.
  • log_on_failure = HOST: Force xinetd to log if there is a connection dropped or if the connection is not allowed to /var/log/secure file
  • cps = 25 30: Limits the rate of incoming connections. Takes two arguments. The first argument is the number of connections per second to handle. If the rate of incoming connections is higher than this, the service will be temporarily disabled. The second argument is the number of seconds to wait efore re-enabling the service after it has been disabled. The default for this setting is 50 incoming connections and the interval is 10 seconds. This is good to avoid DOS attack against your service.
  • includedir /etc/xinetd.d: Read other service specific configuration file this directory.

Task: How to create my own service called foo

Here is sample config file for service called foo located at /etc/xinetd.d/foo
# vi /etc/xinetd.d/foo
And append following text:
service login
socket_type = stream
protocol = tcp
wait = no
user = root
server = /usr/sbin/foo
instances = 20


  • socket_type: Sets the network socket type to stream.
  • protocol: Sets the protocol type to TCP
  • wait: You can set the value to yes or no only. It Defines whether the service is single-threaded (if set to yes) or multi-threaded (if set to no).
  • user: User who will run foo server

Task: Stop or restart xinetd

To restart xinetd service type the command:
# /etc/init.d/xinetd restart
To stop xinetd service type the command:
# /etc/init.d/xinetd stop
To stop xinetd service type the command:
# /etc/init.d/xinetd start

Task: Verify that xinetd is running

Type the following command to verify xinetd service is running or NOT:
# /etc/init.d/xinetd statusOutput:

xinetd (pid 6059) is running...

Further readings

  • Read man pages of xinetd.conf and xinetd for more information.