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&quot;EHLO is the Enhanced SMTP (ESMTP) version of HELO. ESMTP adds a number of essential additions to the SMTP protocol. When this command is sent, the server will respond with the EHLO options that is supports.&quot;<br />
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Taken fromt he gordano site: <a href="http://www.gordano.com/kb.htm?q=316" rel="ugc">http://www.gordano.com/kb.htm?q=316</a>
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"EHLO is the Enhanced SMTP (ESMTP) version of HELO. ESMTP adds a number of essential additions to the SMTP protocol. When this command is sent, the server will respond with the EHLO options that is supports."

Taken fromt he gordano site: http://www.gordano.com/kb.htm?q=316 [http://www.gordano.com/kb.htm?q=316]

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I have a vague understanding as to the difference between the two. I guess what I'm asking is would there be any harm in using straight HELO for all outbound mail?
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I have a vague understanding as to the difference between the two. I guess what I'm asking is would there be any harm in using straight HELO for all outbound mail?

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I appreciate the information. I guess I'll just setup a specific connector for that host and set it to HELO rather than defaulting everything to HELO. I wouldn't want to deprive the client of the ability to use HTML emails.
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I appreciate the information. I guess I'll just setup a specific connector for that host and set it to HELO rather than defaulting everything to HELO. I wouldn't want to deprive the client of the ability to use HTML emails.

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The subject pretty much sums it up. I'm running an Exhcnage 2003 server and having trouble sending to some recipients due to the fact that they are apparently using old mail servers that only respond to HELOs. I'd like to know if there are any significant ramifications to forcing all outbound SMTP connections to use HELO rather than EHLO.
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The subject pretty much sums it up. I'm running an Exhcnage 2003 server and having trouble sending to some recipients due to the fact that they are apparently using old mail servers that only respond to HELOs. I'd like to know if there are any significant ramifications to forcing all outbound SMTP connections to use HELO rather than EHLO.

EHLO vs HELO - Is there any reason NOT to default outbound mail to use HELO?

Interactions between email servers and clients are governed by email protocols. The three most common email protocols are POP, IMAP and MAPI. Most email software operates under one of these (and many products support more than one).  The correct protocol must be selected, and correctly configured, if you want your email account to work.

Email Protocols

Exchange is the server side of a collaborative application product that is part of the Microsoft Server infrastructure. Exchange's major features include email, calendaring, contacts and tasks, support for mobile and web-based access to information, and support for data storage.