#!/bin/sh
# telnet - encourage the use of ssh instead by showing the user
#	   how it's done.
#
# Eric Myers <myers@umich.edu>	- 13 April 2000
# @(#) $Id: telnet,v 2.5 2000/06/16 00:37:18 myers Exp myers $
######################################################################


# First some exceptions:

# @(#) Allow telnet to library server.

if echo "$*" | grep mirlyn
then
  # System telnet should be found here (omit /usr/local/bin)
  PATH="/bin:/usr/bin:/usr/ucb"
  telnet $*
  exit $?
fi

# @(#) Allow telnet if alternate port

if [ $# -gt 1 ]
then
  # System telnet should be found here (omit /usr/local/bin)
  PATH="/bin:/usr/bin:/usr/ucb:/usr/bsd"
  telnet $*
  exit $?
fi


# @(#) Warn them not to use telnet and try ssh instead

trap "echo '    Ouch!'; exit" 2

cat <<EOF1

  ********************************************************************
  You know, you really should be using slogin or ssh instead. They are
  more secure than telnet.  The proper command would be:

        ssh $USER@$1

  Let's try that. Press return to issue the command:

EOF1

# The echo command handles line control differenly in BSD and System V,

X=`echo -n EC ; echo HO`
if [ "$X"  =  "ECHO" ]; then
  BSDNL="-n"; SYSVNL="" # BSD line control
else
  SYSVNL="\c"; BSDNL="" # System V line control
fi

echo $BSDNL "ssh $USER@$1 $SYSVNL"
read X
echo    "ssh $USER@$1                     "

# find ssh here, including /usr/local/bin
PATH="/usr/local/bin:/bin:/usr/bin:/usr/ucb"

# Try it.  If it fails, then try telnet

if ! ssh $USER@$1
then	 
  sleep 2
  clear 
  cat <<EOF2

  Well, okay, it didn't seem to work in this case. But please do read
  more about the dangers of using telnet and the virtues of ssh in:

     http://noether.vassar.edu/~myers/help/SecureShell.html

  We'll try to use telnet now, but keep in mind that YOUR PASWORD IS
  BEING BROADCAST OVER THE INTERNET UNENCRYPTED!

EOF2

  # System telnet should be found here (omit /usr/local/bin)
  PATH="/bin:/usr/bin:/usr/ucb"
  telnet $*
  exit $?

# It worked, and we are back, so thank them.

else
  cat <<EOF3

  Thank you for using ssh instead of telnet.

EOF3

fi