Provided by: xinetd_2.3.14-7ubuntu4_amd64 bug


       xinetd - the extended Internet services daemon


       xinetd [options]


       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 the 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.

       The services listed in xinetd's configuration file  can  be  separated  into  two  groups.
       Services  in  the  first group are called multi-threaded and they require the forking of a
       new server process for each new connection request.  The  new  server  then  handles  that
       connection.   For  such  services,  xinetd keeps listening for new requests so that it can
       spawn new servers.  On the other hand, the second group includes services  for  which  the
       service daemon is responsible for handling all new connection requests.  Such services are
       called single-threaded and xinetd will stop handling  new  requests  for  them  until  the
       server dies.  Services in this group are usually datagram-based.

       So  far,  the  only  reason  for  the  existence  of a super-server was to conserve system
       resources by avoiding to fork a lot of processes which might be dormant for most of  their
       lifetime.   While fulfilling this function, xinetd takes advantage of the idea of a super-
       server to provide features such as access control and logging.  Furthermore, xinetd is not
       limited  to  services listed in /etc/services.  Therefore, anybody can use xinetd to start
       special-purpose servers.


       -d     Enables debug mode. This produces a lot  of  debugging  output,  and  it  makes  it
              possible to use a debugger on xinetd.

       -syslog syslog_facility
              This  option enables syslog logging of xinetd-produced messages using the specified
              syslog facility.  The following facility names are supported: daemon,  auth,  user,
              local[0-7]  (check  syslog.conf(5) for their meanings).  This option is ineffective
              in debug mode since all relevant messages are sent to the terminal.

       -filelog logfile
              xinetd-produced messages will be placed in the specified file.  Messages are always
              appended to the file.  If the file does not exist, it will be created.  This option
              is ineffective in debug mode since all relevant messages are sent to the terminal.

       -f config_file
              Determines  the  file  that  xinetd  uses  for  configuration.   The   default   is

       -pidfile pid_file
              The process ID is written to the file. This option is ineffective in debug mode.

              Tells  xinetd  to  stay  in the foreground rather than detaching itself, to support
              being run from init or daemontools. This option automatically sets -stayalive  (see

              Tells xinetd to stay running even if no services are specified.

       -limit proc_limit
              This option places a limit on the number of concurrently running processes that can
              be started by xinetd.  Its purpose is to prevent process table overflows.

       -logprocs limit
              This option places a limit on the number of concurrently running servers for remote
              userid acquisition.

              This option causes xinetd to print out its version information.

              This  option  causes  xinetd  to  read  /etc/inetd.conf in addition to the standard
              xinetd config files.  /etc/inetd.conf is read  after  the  standard  xinetd  config

              This  option  causes  xinetd  to  bind  to  IPv6  (AF_INET6)  addresses  for  inetd
              compatibility lines (see previous option).  This only affects  how  /etc/inetd.conf
              is  interpreted  and  thus  only has any effect if the -inetd_compat option is also

       -cc interval
              This option instructs xinetd to perform periodic consistency checks on its internal
              state every interval seconds.

       The  syslog and filelog options are mutually exclusive.  If none is specified, the default
       is syslog using the daemon facility.  You should not confuse xinetd messages with messages
       related  to  service  logging.  The  latter  are  logged only if this is specified via the
       configuration file.


       xinetd performs certain actions when it receives certain signals.  The actions  associated
       with the specific signals can be redefined by editing config.h and recompiling.

       SIGHUP         causes  a  hard  reconfiguration,  which  means  that  xinetd  re-reads the
                      configuration file and terminates the servers  for  services  that  are  no
                      longer  available.  Access control is performed again on running servers by
                      checking the remote location, access times and  server  instances.  If  the
                      number of server instances is lowered, some arbitrarily picked servers will
                      be killed to satisfy the limit; this will  happen  after  any  servers  are
                      terminated  because  of  failing the remote location or access time checks.
                      Also, if the INTERCEPT flag was clear and is set, any running  servers  for
                      that  service  will  be  terminated;  the purpose of this is to ensure that
                      after a hard reconfiguration there will be  no  running  servers  that  can
                      accept packets from addresses that do not meet the access control criteria.

       SIGQUIT        causes program termination.

       SIGTERM        terminates all running servers before terminating xinetd.

       SIGUSR1        causes    an    internal   state   dump   (the   default   dump   file   is
                      /var/run/xinetd.dump; to change the filename, edit config.h and recompile).

       SIGABRT        causes an internal consistency check to verify  that  the  data  structures
                      used  by  the program have not been corrupted.  When the check is completed
                      xinetd will generate a message that says if the  check  was  successful  or

       On  reconfiguration  the log files are closed and reopened. This allows removal of old log


       /etc/xinetd.conf    default configuration file
                           default dump file






       Panos Tsirigotis, CS Dept, University of Colorado, Boulder Rob Braun



                                           14 June 2001                                 XINETD(8)