rexecd(1)                                                     rexecd(1)

  rexecd

  NAME

    rexecd - remote execution server

  SYNOPSIS

    rexecd

  DESCRIPTION

    The rexecd(1) utility is the server for the rexec(3) routine. The server
    provides remote execution facilities with authentication based on user
    names and passwords.

    The rexecd(1) utility listens for service requests at the port indicated
    in the "exec" service specification. When a service request is received,
    the following protocol is initiated:

   1.     The server reads characters from the socket up to a NUL (\0) byte.
          The resultant string is interpreted as an ASCII number, base 10.
   2.     If the number received in step 1 is non-zero, it is interpreted as
          the port number of a secondary stream to be used for the stderr. A
          second connection is then created to the specified port on the
          client computer.
   3.     A NUL terminated user name of at most 128 characters is retrieved on
          the initial socket (the value is 16 characters for non-Interix
          systems).
   4.     A NUL terminated, unencrypted password of at most 128 characters is
          retrieved on the initial socket (the value 16 characters for non-
          Interix systems).
   5.     A NUL terminated command to be passed to a shell is retrieved on the
          initial socket. The length of the command is limited by the upper
          bound on the size of the system's argument list.
   6.     The rexecd(1) utility then validates the user as is done at login
          time and, if the authentication was successful, changes to the
          user's home directory, and establishes the user and group
          protections of the user. If any of these steps fails, the connection
          is aborted with a diagnostic message returned.
   7.     A NUL byte is returned on the initial socket and the command line is
          passed to the normal login shell of the user. The shell inherits the
          network connections established by rexecd.(1)

  DIAGNOSTICS

    Except for the last one listed below, all diagnostic messages are returned
    on the initial socket, after which any network connections are closed. An
    error is indicated by a leading byte with a value of 1. A 0 is returned in
    step 7 discussed previously, upon successful completion of all the steps
    prior to the command execution.

    username too long
        The name is longer than 128 characters.

    password too long
        The password is longer than 128 characters.

    command too long
        The command line passed exceeds the size of the argument list (as
        configured into the system).

    Login incorrect.
        No user database entry for the user name existed or the wrong password
        was supplied.

    No remote directory.
        The chdir(1) command to the home directory failed.

    Try again.
        A fork(2) by the server failed.

    : ...
        The user's login shell could not be started. This message is returned
        on the connection associated with the stderr, and is not preceded by a
        flag byte.

  SEE ALSO

    rexec(3)