4.3BSD - /usr/man/cat8/rlogind.0

RLOGIND(8C)                                                        RLOGIND(8C)


NAME
       rlogind - remote login server

SYNOPSIS
       /etc/rlogind [ -d ]

DESCRIPTION
       Rlogind  is the server for the rlogin(1C) program.  The server provides
       a remote login facility with authentication based  on  privileged  port
       numbers from trusted hosts.

       Rlogind  listens  for  service  requests  at  the port indicated in the
       ‘‘login’’ service  specification;  see  services(5).   When  a  service
       request is received the following protocol is initiated:

       1)     The  server checks the client’s source port.  If the port is not
              in the range 0-1023, the server aborts the connection.

       2)     The server checks the client’s source address and  requests  the
              corresponding  host  name  (see  gethostbyaddr(3N), hosts(5) and
              named(8)).  If the hostname cannot be determined, the  dot-nota‐
              tion representation of the host address is used.

       Once the source port and address have been checked, rlogind allocates a
       pseudo terminal (see pty(4)), and manipulates file descriptors so  that
       the  slave half of the pseudo terminal becomes the stdin , stdout , and
       stderr for a login process.  The login process is an  instance  of  the
       login(1)  program,  invoked with the -r option.  The login process then
       proceeds with the authentication process as described in rshd(8C),  but
       if  automatic  authentication  fails, it reprompts the user to login as
       one finds on a standard terminal line.

       The parent of the login process manipulates the master side of the pse‐
       duo  terminal,  operating  as an intermediary between the login process
       and the client instance of the rlogin program.   In  normal  operation,
       the  packet  protocol  described  in pty(4) is invoked to provide ^S/^Q
       type facilities and propagate interrupt signals to the remote programs.
       The login process propagates the client terminal’s baud rate and termi‐
       nal type, as found in the environment  variable,  ‘‘TERM’’;  see  envi���
       ron(7).   The  screen  or window size of the terminal is requested from
       the client, and window size changes from the client are  propagated  to
       the pseudo terminal.

DIAGNOSTICS
       All  diagnostic messages are returned on the connection associated with
       the stderr, after which any network connections are closed.   An  error
       is indicated by a leading byte with a value of 1.

       ‘‘‘‘Try again.’’’’
       A fork by the server failed.

       ‘‘‘‘/bin/sh: ...’’’’
       The user’s login shell could not be started.

BUGS
       The  authentication  procedure  used here assumes the integrity of each
       client machine and the connecting medium.  This  is  insecure,  but  is
       useful in an ‘‘open’’ environment.

       A  facility  to  allow  all  data  exchanges  to be encrypted should be
       present.

       A more extensible protocol should be used.


4.2 Berkeley Distribution        May 24, 1986                      RLOGIND(8C)