sendmail

[Ed Greshko]

On 07/09/2012 03:37 PM, roland wrote:
> I suppose that if one uses the ESMTP option, one has to install esmtp and configure
> it as needed.
> as discribed in :
> http://www.techrepublic.com/blog/opensource/send-mail-with-esmtp-for-a-simple-single-user-system/232
>
> How do you tell sendmail to use esmtp as the email deliverer?
>
> I dropped that line and  used a authinfo file as described above and it worked.
> Probably is esmtp a simpler way to do it for different users and different domains? 

Ahhh.... 

SMTP=Simple Mail Transfer Protocol
ESMTP=Extended Simple Mail Transfer Protocol

ESMTP added a framework to SMTP to add additional commands into the SMTP protocol to
extend the usefulness.

You can see what extensions are currently supported by your version your sendmail, or
any MTA, by issuing the ehlo command instead of the helo command.

[egreshko at f17 ~]$ telnet localhost 25
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
220 f17.greshko.com ESMTP Sendmail 8.14.5/8.14.5; Mon, 9 Jul 2012 16:09:07 +0800
helo f17.greshko.com
250 f17.greshko.com Hello localhost [127.0.0.1], pleased to meet you

as opposed to

[egreshko at f17 ~]$ telnet localhost 25
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
220 f17.greshko.com ESMTP Sendmail 8.14.5/8.14.5; Mon, 9 Jul 2012 16:06:45 +0800
ehlo f17.greshko.com
250-f17.greshko.com Hello localhost [127.0.0.1], pleased to meet you
250-ENHANCEDSTATUSCODES
250-PIPELINING
250-8BITMIME
250-SIZE
250-DSN
250-ETRN
250-AUTH GSSAPI DIGEST-MD5 CRAM-MD5
250-DELIVERBY
250 HELP

Port 587 and AUTH are 2 different things....

Port 587 is SMTP or ESMTP over SSL.  The connection is secured by SSL in the same
manner as HTTPS.  HTTP uses port 80 while HTTPS uses 443.  But the underlying
protocol is the same.  Same goes here.

AUTH is part of ESMTP and defined in rfc4954.  It is an Authentication mechanism and
is available via non encrypted (port 25) or encrypted (port 587) connections to the
MTA. 

I don't know if that clears anything up for you.....


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