You didn't configure your Exchange server to accept mails for slopez@alrconsultores.com
. So it tries to inform admin@alrconsultores.com
about that situation. But unfortunately this user is unknown, too.
So configure your Exchange to accept both mail addresses and the problem is gone.
Finally figured it out after a lot of scrutinizing log files.
The e-mail client was sending DATA
but the internal SMTP server was sending it out to the smart host via BDAT
and evidently this is a potential DDoS issue and I guess somewhere along the way it was not allowing it to process properly. It's possible that our SonicWall
firewall was screwing with it some how also.
Offending Line:
2016-05-17 13:12:32 66.110.xx.xxx OutboundConnectionCommand MAILSVR01 - 25 BDAT 43574+LAST 0 0 4 0 16 SMTP - -
So the solution was to disable BDAT, BINARYMIME and CHUNKING on the local SMTP Server.
Credit/Source Link:
https://adaptivethinking.wordpress.com/2010/12/21/smtp-esmtp-and-the-bdat-baddie/
https://joekiller.com/2007/09/19/bdat-causing-smtp-service-to-drop-email/
In case the link is no longer available here are the steps they outlined.
Telnet to the mail host and issue the ehlo
command. Check the verbs the server returns. It should have BINARYMIME
and CHUNKING
listed. After these steps you will not have these.
Verify BINARYMIME
and CHUNKING
are turned on.:
telnet localhost 25
Type ehlo
220 MAILSVR Microsoft ESMTP MAIL Service, Version: 7.5.76
01.17514 ready at Tue, 14 Mar 2017 12:18:50 -0400
ehlo
250-MAILSVR Hello [168.1.1.1]
250-TURN
250-SIZE 51200000
250-ETRN
250-PIPELINING
250-DSN
250-ENHANCEDSTATUSCODES
250-BINARYMIME
250-CHUNKING
250-8bitmime
250-VRFY
250-TLS
250-STARTTLS
250 OK
Install IIS6.0 Resource Kit
Open IIS Metabase Explorer
Navigate to LM\SmtpSvc\1
Look for SmtpInboundCommandSupportOptions
Here the default value was 7697601
. I knew that I wanted to disable the BINARYMIME and CHUNKING verbs so using the table here I subtracted 2097152
(BINARYMIME) and 1048576
(CHUNKING) from 7697601
:
7697601 - (2097152 + 1048576) = 4551873
Set the SmtpInboundCommandSupportOptions
value to 4551873
Disable BDAT
Navigate to LM\SmtpSvc
Change value of SmtpOutboundCommandSupportOptions
from 7
to 5
Close the IIS Metabase Explorer
and restarted the IIS Admin Service
(which in turn restarts the Simple Mail Transfer Protocol
(SMTP) service).
Repeat the steps to connect to the server via telnet
and verify they have been removed. If they have not make sure you are in the \1
subdirectory when you make the changes.
Best Answer
following these instructions on windows 2003 (IIS6):
http://routerjanitor.blogspot.com/2011/08/google-apps-iis-smtp-relay.html
I have exact the same info added, but only in the header.
Tested sending both a gmail account and a normal account. We do use postini though, so that adds some more to the headers before the message gets delivered.