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The Difference Between HELO and EHLO?"

orosie68 asked
Last Modified: 2012-10-19
The Difference Between HELO and EHLO?"
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Dear orosie68,
EHLO indicates that the client supports at least one of several possible extensions that are not part of the basic SMTP specification. HELO indicates that it does not, and that only the minimum SMTP set will be used when talking to this server. Many of these extensions are common and standardized; others may be local to the particular SMTP host only, in which case, the extended commands must begin with the letter X. All extended commands the server supports must be listed as part of the server’s response to EHLO, one per line, each line prefixed with code 250. Typical uses of extended commands are to transfer binary information in non-encoded form, and to tunnel another protocol through SMTP.

refer : http://www.microsoft.com/technet/technetmag/issues/2005/11/HowITWorksSMTP/?related=/technet/technetmag/issues/2005/11/HowITWorksSMTP

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HELO <hostname> Introduce yourself.

EHLO <hostname> Introduce yourself and request extended SMTP mode.

where <hostname> is your computer

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