LISTEN(8)                                               LISTEN(8)

     NAME
          listen, dkcpu, dkcpunote, dkdiscard, dkecho, dkexportfs,
          dkrexexec, dkticket, dkwhoami, dksmtp, dkdcon, dklogin,
          dkguard, il7, il9, il565, il566, il17005, il17006, il17007,
          il17009, tcp2, tcp7, tcp9, tcp21, tcp23, tcp80, tcp25,
          tcp513, tcp515, tcp564, tcp565, tcp566, tcp17007, tcp6000 -
          listen for calls on a network device

     SYNOPSIS
          aux/listen [-q] [-d srvdir] [-t trustsrvdir] [net [name]]

     DESCRIPTION
          listen announces itself to a network as name (by default the
          contents of /env/sysname) and listens for inbound calls to
          local services.  Net is the network device on which to lis-
          ten, by default /net/dk.  The services available are exe-
          cutable files in srvdir or trustsrvdir. If neither srvdir
          nor trustsrvdir is given, listen looks for executable files
          in /bin/service.  Services found in srvdir are executed as
          user none; services found in trustsrvdir as executed as the
          user who started listen. Option -q suppresses affirmative
          log information.

          Service names are made by concatenating the name of the net-
          work with the name of the service or port.  For example, an
          inbound call on the TCP network for port 565 executes ser-
          vice tcp565, while a call on the Datakit network for service
          whoami executes service dkwhoami.

          The following services are available in /bin/service.

          dkcpu il17005          server for cpu(1) command.
          dkcpunote il17006      /proc/pid/notify forwarding for
                                 cpu(1).
          dkexportfs il17007 tcp17007
                                 serve a piece of the name space using
                                 the Plan 9 file system protocol, with
                                 authentication (typically used by
                                 cpu(1)).
          tcp564                 like 17007, without authentication
                                 (used by Unix systems to see Plan 9
                                 files).
          dkrexexec il17009      remote execution.
          dkwhoami il565 tcp565  report the address of the incoming
                                 call.
          tcp21                  FTP daemon
          tcp80                  HTTP daemon; see httpd(8).
          tcp515                 LP daemon; see lp(8).
          tcp6000                X-window callback
          dksmtp tcp25           mail delivery.

     LISTEN(8)                                               LISTEN(8)

          dkdcon                 research Unix terminal connection.
          dklogin                generic terminal connection.
          tcp23                  telnet terminal connection.
          tcp513                 rlogin terminal connection.
          tcp2                   hold the connection open; sleep for a
                                 long time
          dkecho il7 tcp7        echo any bytes received (bit mirror)
          dkdiscard il9 tcp9     consume any bytes received (bit
                                 bucket)

          The following services are available in /bin/service.auth.
          dkguard tcp566         check a SecureNet box.
          dkticket il566         authentication requests.

     FILES
          /net/dk       by convention, Datakit device bind point
          /net/il       by convention, IL device bind point
          /net/tcp      by convention, TCP device bind point
          /env/sysname  default announced name

     SOURCE
          The source to listen is in /sys/src/cmd/aux/listen.c.  The
          other commands are rc(1) scripts in /rc/bin/service.

     SEE ALSO
          dkconfig(8), auth(6), dk(3), dial(2)