#!/usr/bin/perl
# Simple perl script to reject email at the SMTP level.
# Please send any comments, etc to the author, pb@cl.cam.ac.uk

# Collect the supplied args, hostname and date
$info = join(" ", @ARGV); undef(@ARGV);
chop($host = `uname -n || hostname`);
chop($date = `date`);
$msg = "All email should be sent to user\@cl.cam.ac.uk and NOT to a specific machine";

$| = 1;	# do not buffer IO

print "220 $host SMTP email rejecter ready at $date.$info\r\n";
while (<>) {
	last if /^quit/i;
	if (/^hel[op]/i) { print "250 $host Hello there - I shall reject all mail you send\r\n"; }
	elsif (/^mail *from:/i) { print "250 I accept any sender address but I shall reject all email\r\n"; }
	elsif (/^rcpt *to:[ 	]*([^\n\r]*)/i) { print "550 $msg (e.g. $1)\r\n"; }
	elsif (/^vrfy/i || /^expn/i) { print "550 $msg\r\n"; }
	elsif (/^data/i) { print "503 No recipeints are ever valid\r\n"; }
	elsif (/^rset/i | /^noop/i | /^debug/i) { print "250 OK\r\n"; }
	else { print "500 Command unrecognized.\r\n"; }
}
print "221 $host closing connection.  Goodbye.\r\n";