Mail ehlo

A classic!

EHLO is a command in the Simple Mail Transfer Protocol (SMTP) that is used to initiate a connection with a mail server. It's similar to the HELO command, but EHLO is used to negotiate extensions to the SMTP protocol.

When you send an EHLO command, you're essentially saying "Hello, I'd like to start a conversation with you about sending email."

Here's a breakdown of the EHLO command:

• EHLO is the command itself, which stands for "Extended Hello".
• The domain name or hostname of the sending mail server is usually included after the EHLO command, separated by a space. For example: EHLO example.com

When a mail server receives an EHLO command, it responds with a greeting message that includes its own domain name and a list of supported extensions to the SMTP protocol. This allows the sending mail server to determine which features are available for use in the email transmission.

For example, a typical response to an EHLO command might look like this:

220 example.com ESMTP Postfix (Ubuntu)

This response indicates that the mail server is example.com, running Postfix (a popular mail transfer agent), and is running on Ubuntu. The (Ubuntu) part is just a hint about the operating system being used.

So, to summarize: EHLO is a command used to initiate a connection with a mail server and negotiate extensions to the SMTP protocol. It's an essential part of the email transmission process!