Sending SMTP Commands with /dev/tcp

gistfile1.txt

#!/bin/bash
 
# Written by: Terry Moore
# Created on Date: 2009-10-12
# Test mail relay from a Linux database server 
# Version 0.2 
# Last update 2009-10-13
 
#Body of Email
DATA="The test message has been sent"
 
#Subject of Email
SUBJECT="Mail Relay Test"
 
 
######### Header ##########
echo
echo
echo
echo "***************************************"
echo "*                                                           *"
echo "*             Mail Relay Test App                    *"
echo "*                                                           *"
echo "***************************************"
echo 
echo "Press control+c at any time to cancel"
echo "Please answer all of the following questions:"
echo
 
 
##### Get Mail Server #######
LOOP=0
while [ $LOOP -ne 1  ]
do
	echo -n "Enter Mail Server Name: " ; read MAILSERVER;
	if [ "$MAILSERVER" != '' ] ; then
		LOOP=1
	fi
done
 
 
###### GET PORT ##########
echo -n "Enter Port: [typically 25]: "; read PORT;
if [ "$PORT" = '' ] ; then
	LOOP=1
	PORT="25"
fi
 
###### GET MAIL FROM ##########
echo -n "Enter Mail From: [support@email.com]" ; read MAILFROM
if [ "$MAILFROM" = '' ] ; then
	MAILFROM="support@email.com"
	LOOP=0
fi
 
###### GET MAIL TO ##########
LOOP=0
while [ $LOOP -ne 1 ]
do
	echo -n "Enter Mail To: " ; read MAILTO
	if [ "$MAILTO" != '' ] ; then
		LOOP=1
	fi
done
 
 
#### SEND MAIL via RAW TCP #######
echo 
echo "Connecting to $MAILSERVER on Port $PORT";
echo "Please wait ... "
echo
exec 3<>/dev/tcp/$MAILSERVER/$PORT 
 
if [ $? -ne 0 ] ; then
	echo
	echo "ERROR: Cannot connect to the Mail Server";
	echo "Please check the servername and/or the port number"
	exit
fi
 
echo -en "HELO mail.email.com\r\n"  >&3 
echo -en "MAIL FROM:$MAILFROM\r\n" >&3
echo -en "RCPT TO:$MAILTO\r\n" >&3
echo -en "DATA\r\n" >&3
echo -en "Subject: $SUBJECT\r\n\r\n" >&3
echo -en "$DATA\r\n" >&3
echo -en ".\r\n" >&3
echo -en "QUIT\r\n" >&3
cat <&3
 
 
echo
echo
echo "Check the above output for errors"
echo