Provided by: xinetd_2.3.15.3-1_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

       -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


       REMOTE_HOST Contains the IP address of the client.






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



                                           14 June 2001                                 XINETD(8)