Email notification using the SMTP/Pop3 protocol troubleshooting

Answer

These steps should be used to validate whether that the SMTP Server is working properly:

1. Open a telnet connection to the mail server using port 25.
   From the command prompt enter the following command:
   
telnet mailserver 25

   Response:
   
220 mailserver ESMTP

   If the server does not accept the connection, the client quits.
   
   
2. If a connection is established, enter the following client command to send a HELO request and wait for the response:
   
HELO yourdomainname

   Response:
   
250 user1.domain.com Hello, pleased to meet you

   If the server does not accept the request, the client quits.
   
   
3. Enter the following client command to send a MAIL request showing the envelope sender address, and wait for the response:
   
MAIL FROM:<reqpro@domain.com>

   Response:
   
250 ok

   If a 250 line appears, the send was successful.
   If the server does not accept the request, the client quits.
   
   
4. Enter the following client command to send one RCPT request for each envelope recipient address and wait for a response after each address:
   
RCPT TO:<user1@domain.com>

   Response:
   
250 ok

   If a 250 line appears, the send was successful. Keep track of which addresses are accepted.
   If none of the addresses are accepted, the client quits.
   
   
5. Enter the following client command to send a DATA request and wait for the response:
   
DATA

   Response:
   
354 go ahead

   The 354 line indicates that a message can be entered.
   If the server does not accept the request, the client quits.
   
   
6. Enter the following client commands to send the encoded message, ending with "." on a line by itself:
   
Date: 31 Dec 2001 04:10:45 -0000
From: reqpro@domain.com
To: user1@domain.com
Subject: reqpro

Testing SMTP for reqpro email notification.
. <--(a period on its own ends the message)

   Response:
   
250 ok

   The 250 line concludes this simple test.