Returned mail: "Polite people say HELO first"

[Michael Ebbert]

Please let me know if you've seen the following undeliverable message report and know how to resolve it. I have a feeling it has to do with Microsoft's implementation of the RFC SMTP standards being slightly different from that of other mail systems (or routers?).

Your message did not reach some or all of the intended recipients.

Subject: <msg subject>
Sent: 5/5/99 2:52 PM

The following recipient(s) could not be reached:

'username@domain.com' on 5/5/99 2:52 PM
Unable to deliver the message due to a communications failure
MSEXCH:IMS:<company name>:<site name>:SERVERNAME 3503 (000B099C) 503 Polite people say HELO first

[jimmy]

turn on "SMTP protocol logging" in the IMC. look into the logs under exchsrvrimcdatalog. remember to turn it off when done.


------------
Michael Ebbert at 5/13/99 8:29:20 AM

Please let me know if you've seen the following undeliverable message report and know how to resolve it. I have a feeling it has to do with Microsoft's implementation of the RFC SMTP standards being slightly different from that of other mail systems (or routers?).

Your message did not reach some or all of the intended recipients.

Subject: <msg subject>
Sent: 5/5/99 2:52 PM

The following recipient(s) could not be reached:

'username@domain.com' on 5/5/99 2:52 PM
Unable to deliver the message due to a communications failure
MSEXCH:IMS:<company name>:<site name>:SERVERNAME 3503 (000B099C) 503 Polite people say HELO first

[jimmy]

turn on "SMTP protocol logging" in the IMC. look into the logs under exchsrvrimcdatalog. remember to turn it off when done.


------------
Michael Ebbert at 5/13/99 8:29:20 AM

Please let me know if you've seen the following undeliverable message report and know how to resolve it. I have a feeling it has to do with Microsoft's implementation of the RFC SMTP standards being slightly different from that of other mail systems (or routers?).

Your message did not reach some or all of the intended recipients.

Subject: <msg subject>
Sent: 5/5/99 2:52 PM

The following recipient(s) could not be reached:

'username@domain.com' on 5/5/99 2:52 PM
Unable to deliver the message due to a communications failure
MSEXCH:IMS:<company name>:<site name>:SERVERNAME 3503 (000B099C) 503 Polite people say HELO first

[Michael Ebbert]

I resolved this issue myself by disabling a feature of Exchange. Here are the details:

Sorry about the disclaimer, but please take anything you hear from me or
anyone else on the Internet and apply your own judgement to it, as you are
ultimately responsible for your own systems. Apply at your own risk!

OK, here is what I found out. If you check out the original RFC 821
document detailing SMTP standards, there is no mention of initiating
connections with an "EHLO". See http://www.faqs.org/rfcs/std/std10.html

In Nov. 1995 the standards for SMTP were appended with RFC 1869, see
http://www.faqs.org/rfcs/rfc1869.html and the new "extensions" to SMTP
communication required that EHLO be created to differentiate between
connections using RFC821 compliant SMTP systems and RFC1869 compliant
ESMTP systems.

Now there are several proper responses to an EHLO command during SMTP
transfer. One is 502, which means that EHLO on the host is not supported. Another response would be 250, which in SMTP language basically means "your
last command was OK". After a 250 response, ESMTP (SMTP with extensions)
communication should be able to proceed successfully. In my Exchange
server IMC log file, the EHLO command was met with a response of 220. However, 220 is the command used when an SMTP connection is first initiated. Therefore one would think that 220 is an improper response to an EHLO command. The Exchange server appeared to interpret the 220 as a "go ahead and transmit" type of response, which it is not.

Then when the MAIL FROM command was sent next, the host responded correctly with 503, which means commands are out of order. This is because MAIL FROM is not valid until an EHLO or HELO command is successful.

Why was this happening? I believe that not every SMTP program on the
internet is fully compliant with RFC1869. Since each one is different, some
mail servers were responding to our Exchange server EHLO requests properly,
and some were not.

What to do to resolve the problem? Well, we could begin contacting all
these companies and politely ask them to update THEIR systems, or we could
disable the ESMTP outgoing protocol on our Exchange servers. We decided to disable ESMTP and see if we were able to send mail to everyone after that.

The Microsoft article detailing how to disable ESMTP is Q194132.
http://support.microsoft.com/support/kb/articles/q194/1/32.asp

After implementing this change, we have not received any more of the "Polite People say HELO first" messages.

------------
Michael Ebbert at 5/13/99 8:29:20 AM

Please let me know if you've seen the following undeliverable message report and know how to resolve it. I have a feeling it has to do with Microsoft's implementation of the RFC SMTP standards being slightly different from that of other mail systems (or routers?).

Your message did not reach some or all of the intended recipients.

Subject: <msg subject>
Sent: 5/5/99 2:52 PM

The following recipient(s) could not be reached:

'username@domain.com' on 5/5/99 2:52 PM
Unable to deliver the message due to a communications failure
MSEXCH:IMS:<company name>:<site name>:SERVERNAME 3503 (000B099C) 503 Polite people say HELO first

[Michael Ebbert]

I resolved this issue myself by disabling a feature of Exchange. Here are the details:

Sorry about the disclaimer, but please take anything you hear from me or
anyone else on the Internet and apply your own judgement to it, as you are
ultimately responsible for your own systems. Apply at your own risk!

OK, here is what I found out. If you check out the original RFC 821
document detailing SMTP standards, there is no mention of initiating
connections with an "EHLO". See http://www.faqs.org/rfcs/std/std10.html

In Nov. 1995 the standards for SMTP were appended with RFC 1869, see
http://www.faqs.org/rfcs/rfc1869.html and the new "extensions" to SMTP
communication required that EHLO be created to differentiate between
connections using RFC821 compliant SMTP systems and RFC1869 compliant
ESMTP systems.

Now there are several proper responses to an EHLO command during SMTP
transfer. One is 502, which means that EHLO on the host is not supported. Another response would be 250, which in SMTP language basically means "your
last command was OK". After a 250 response, ESMTP (SMTP with extensions)
communication should be able to proceed successfully. In my Exchange
server IMC log file, the EHLO command was met with a response of 220. However, 220 is the command used when an SMTP connection is first initiated. Therefore one would think that 220 is an improper response to an EHLO command. The Exchange server appeared to interpret the 220 as a "go ahead and transmit" type of response, which it is not.

Then when the MAIL FROM command was sent next, the host responded correctly with 503, which means commands are out of order. This is because MAIL FROM is not valid until an EHLO or HELO command is successful.

Why was this happening? I believe that not every SMTP program on the
internet is fully compliant with RFC1869. Since each one is different, some
mail servers were responding to our Exchange server EHLO requests properly,
and some were not.

What to do to resolve the problem? Well, we could begin contacting all
these companies and politely ask them to update THEIR systems, or we could
disable the ESMTP outgoing protocol on our Exchange servers. We decided to disable ESMTP and see if we were able to send mail to everyone after that.

The Microsoft article detailing how to disable ESMTP is Q194132.
http://support.microsoft.com/support/kb/articles/q194/1/32.asp

After implementing this change, we have not received any more of the "Polite People say HELO first" messages.

------------
Michael Ebbert at 5/13/99 8:29:20 AM

Please let me know if you've seen the following undeliverable message report and know how to resolve it. I have a feeling it has to do with Microsoft's implementation of the RFC SMTP standards being slightly different from that of other mail systems (or routers?).

Your message did not reach some or all of the intended recipients.

Subject: <msg subject>
Sent: 5/5/99 2:52 PM

The following recipient(s) could not be reached:

'username@domain.com' on 5/5/99 2:52 PM
Unable to deliver the message due to a communications failure
MSEXCH:IMS:<company name>:<site name>:SERVERNAME 3503 (000B099C) 503 Polite people say HELO first

[Michael Ebbert]

I resolved this issue myself by disabling a feature of Exchange. Here are the details:

Sorry about the disclaimer, but please take anything you hear from me or
anyone else on the Internet and apply your own judgement to it, as you are
ultimately responsible for your own systems. Apply at your own risk!

OK, here is what I found out. If you check out the original RFC 821
document detailing SMTP standards, there is no mention of initiating
connections with an "EHLO". See http://www.faqs.org/rfcs/std/std10.html

In Nov. 1995 the standards for SMTP were appended with RFC 1869, see
http://www.faqs.org/rfcs/rfc1869.html and the new "extensions" to SMTP
communication required that EHLO be created to differentiate between
connections using RFC821 compliant SMTP systems and RFC1869 compliant
ESMTP systems.

Now there are several proper responses to an EHLO command during SMTP
transfer. One is 502, which means that EHLO on the host is not supported. Another response would be 250, which in SMTP language basically means "your
last command was OK". After a 250 response, ESMTP (SMTP with extensions)
communication should be able to proceed successfully. In my Exchange
server IMC log file, the EHLO command was met with a response of 220. However, 220 is the command used when an SMTP connection is first initiated. Therefore one would think that 220 is an improper response to an EHLO command. The Exchange server appeared to interpret the 220 as a "go ahead and transmit" type of response, which it is not.

Then when the MAIL FROM command was sent next, the host responded correctly with 503, which means commands are out of order. This is because MAIL FROM is not valid until an EHLO or HELO command is successful.

Why was this happening? I believe that not every SMTP program on the
internet is fully compliant with RFC1869. Since each one is different, some
mail servers were responding to our Exchange server EHLO requests properly,
and some were not.

What to do to resolve the problem? Well, we could begin contacting all
these companies and politely ask them to update THEIR systems, or we could
disable the ESMTP outgoing protocol on our Exchange servers. We decided to disable ESMTP and see if we were able to send mail to everyone after that.

The Microsoft article detailing how to disable ESMTP is Q194132.
http://support.microsoft.com/support/kb/articles/q194/1/32.asp

After implementing this change, we have not received any more of the "Polite People say HELO first" messages.

------------
Michael Ebbert at 5/13/99 8:29:20 AM

Please let me know if you've seen the following undeliverable message report and know how to resolve it. I have a feeling it has to do with Microsoft's implementation of the RFC SMTP standards being slightly different from that of other mail systems (or routers?).

Your message did not reach some or all of the intended recipients.

Subject: <msg subject>
Sent: 5/5/99 2:52 PM

The following recipient(s) could not be reached:

'username@domain.com' on 5/5/99 2:52 PM
Unable to deliver the message due to a communications failure
MSEXCH:IMS:<company name>:<site name>:SERVERNAME 3503 (000B099C) 503 Polite people say HELO first

[Michael Ebbert]

I resolved this issue myself by disabling a feature of Exchange. Here are the details:

Sorry about the disclaimer, but please take anything you hear from me or
anyone else on the Internet and apply your own judgement to it, as you are
ultimately responsible for your own systems. Apply at your own risk!

OK, here is what I found out. If you check out the original RFC 821
document detailing SMTP standards, there is no mention of initiating
connections with an "EHLO". See http://www.faqs.org/rfcs/std/std10.html

In Nov. 1995 the standards for SMTP were appended with RFC 1869, see
http://www.faqs.org/rfcs/rfc1869.html and the new "extensions" to SMTP
communication required that EHLO be created to differentiate between
connections using RFC821 compliant SMTP systems and RFC1869 compliant
ESMTP systems.

Now there are several proper responses to an EHLO command during SMTP
transfer. One is 502, which means that EHLO on the host is not supported. Another response would be 250, which in SMTP language basically means "your
last command was OK". After a 250 response, ESMTP (SMTP with extensions)
communication should be able to proceed successfully. In my Exchange
server IMC log file, the EHLO command was met with a response of 220. However, 220 is the command used when an SMTP connection is first initiated. Therefore one would think that 220 is an improper response to an EHLO command. The Exchange server appeared to interpret the 220 as a "go ahead and transmit" type of response, which it is not.

Then when the MAIL FROM command was sent next, the host responded correctly with 503, which means commands are out of order. This is because MAIL FROM is not valid until an EHLO or HELO command is successful.

Why was this happening? I believe that not every SMTP program on the
internet is fully compliant with RFC1869. Since each one is different, some
mail servers were responding to our Exchange server EHLO requests properly,
and some were not.

What to do to resolve the problem? Well, we could begin contacting all
these companies and politely ask them to update THEIR systems, or we could
disable the ESMTP outgoing protocol on our Exchange servers. We decided to disable ESMTP and see if we were able to send mail to everyone after that.

The Microsoft article detailing how to disable ESMTP is Q194132.
http://support.microsoft.com/support/kb/articles/q194/1/32.asp

After implementing this change, we have not received any more of the "Polite People say HELO first" messages.

------------
Michael Ebbert at 5/13/99 8:29:20 AM

Please let me know if you've seen the following undeliverable message report and know how to resolve it. I have a feeling it has to do with Microsoft's implementation of the RFC SMTP standards being slightly different from that of other mail systems (or routers?).

Your message did not reach some or all of the intended recipients.

Subject: <msg subject>
Sent: 5/5/99 2:52 PM

The following recipient(s) could not be reached:

'username@domain.com' on 5/5/99 2:52 PM
Unable to deliver the message due to a communications failure
MSEXCH:IMS:<company name>:<site name>:SERVERNAME 3503 (000B099C) 503 Polite people say HELO first