How SMTP Functions Handle the HELO Command

Keywords: 	   HELO Command

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Question:

Hi there, When I do a port 25 telnet to my mail server, I can send SMTP e-mail by specifying my domain name in the HELO command. For example: HELO MYDOMAIN.COM.

When I Use the Winbatch Internet Extender, I can send mail without error, but the messages do not arrive. I guess the mail server does not accept them. Does this have something to do with the HELO command?

It's not that the body get's lost, the entire message will not be sent. My guess is that the HELO command must be specified. Some servers require this syntax: HELO MYDOMAIN.COM Others will work with only the HELO command. Maybe there's a problem. I Do not know what HELO command WinBatch sends, since I cannot look into theExtender DLL's.

Answer:

The HELO command is the first part of a mail-sending SMTP transaction where the Internet extender first tries to send mail.

The Internet extender looks at the FROM address and extracts the stuff BEHIND the @ sign (for example if the from address is abc@def.com it gets the DEF.COM part and makes a HELO command like:

	HELO def.com

to start off the communication with the mail server.

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Article ID:   W12676

Filename:   How SMTP Functions Handle the HELO Command.txt