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The connection was dropped due to an SMTP protocol event sink

Posted on 2009-04-27
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Last Modified: 2012-08-14
We have an Exchange 2003 server running on Windows Server 2003. The problem is that we are not able to send emails to one domain. The emails get stuck in the exchange queue and the only message we get is the connection was dropped due to an SMTP protocol event sink.
Please help

Thanks
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Question by:solution786
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23 Comments
 
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Expert Comment

by:Mestha
ID: 24244100
That is a bit of generic error. It usually means the remote site is rejecting your email for some reason - lack of reverse DNS/PTR records, invalid name in the SMTP banner, something like that. The message is being dropped at the point of delivery, so I doubt if it is content.

Do you have everything setup correctly for email delivery?

Simon.
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Author Comment

by:solution786
ID: 24244153
Yes everything is setup fine...its just only one domain to which we are not able to send emails.
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Expert Comment

by:energeticbala18
ID: 24245456
If we are not able to send emails to one specific domain, the basic steps that we can do use try telnet to the remote domain and dropp email

do nslookup
type set q=mx
type the domain name
notedown the mx record of the domain to which we are not able to send emails
type telnet mx record of the remote domain 25 and then hit enter
type ehlo and hit enter
type mail from: sender email address and then hit enter
type rcpt to: receiver email address and then hit enter
type data and then hit enter
type test email and hit enter
type "." period symbol and hit enter
verify did we get mail queued for delivery

Note: 1)incase when we telnet to the mx of the remote domain are we able to see the banner proparly ?
          2) are we getting any error message while telnet to the mx?
          3) if the telnet is working fine then try creating a dedicated SMTP connector with smart host of the remote domain MX record

also please enable the NCSA log on the virtual server so that we can triggered if there is any communication issue
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Author Comment

by:solution786
ID: 24245622
When I telnet the mx record  (208.84.244.133) of the remote domain I get following:
450 4.7.1 Client host rejected: cannot find your host name,  [x.x.x.x]
421 4.4.2 quesnel.terra.com Error: timeout exceeded
Connection to host lost

Note x.x.x.x is the ip address of my domain
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Expert Comment

by:Mestha
ID: 24245701
They are rejecting your IP address for some reason. It looks like a lack of reverse DNS entry.

terra.com is a major ISP, I think in Latin America.

Simon.
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Author Comment

by:solution786
ID: 24245753
Simon,
How can I setup reverse DNS entry?
Thanks
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Expert Comment

by:energeticbala18
ID: 24248440
If that the case, you might need to contact your ISP to create Reverse DNS (i.e PTR)
on th CMD prompt
type nslookup hit enter
type set q=txt hit enter
type your smtp domain name
are you able to see the results with some reverse value? if yes just make sure it is correct
OR else you can verify whether you had PTR on the below link
http://postmaster.aol.com/tools/rdns.html

Most of the TIme the PTR record will be created for connecting IP
ask your ISP to created reverse PTR  for the connecting IP

THNKS



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Author Comment

by:solution786
ID: 24254867
When I run the nslookup command with set q=txt I get the following result
"v=spf1 a mx ptr mx:mail.mydomain.ca include:caffary.net -all"

The reverse dns entry is correct.
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Accepted Solution

by:
Mestha earned 2000 total points
ID: 24255323
The NDR looks like it is unable to get your reverse DNS record, that could be an issue with the remote ISP.

If it is just that one host/ISP, then routing your email for that domain via your ISPs SMTP server using a smart host.

Simon.
0
 

Author Comment

by:solution786
ID: 24259855
Simon
The message the connection was dropped due to an SMTP protocol event sink was in the Exchange queue and not iin the NDR. The NDR I received says the following:

Reporting-MTA: dns;mail.mydomain.ca
Final-Recipient: rfc822;jtieppo@ncgames.com.br
Action: delayed
Status: 4.4.7
Will-Retry-Until: Wed, 29 Apr 2009 10:22:27 -0400
X-Display-Name: jtieppo@ncgames.com.br
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Expert Comment

by:energeticbala18
ID: 24262003
the NDR clearly says that it is been delayed and exchange will try to redeliver in several interval
question to you :

what kind anit spam you are using in exchange ?
are you using any 3rd pary disclaimer for exchange?
any smart host?

we can also isolate whether exchange is an issue or not

if you have any workstation were SMTP is installed, if yes then create a smtp connector with smarthost of the workstation with addressspace of that the particular domain
then try to send the email  and if exchange is properly sending the email to that smtp workstation then we need to look for the above mentioned questions and finally you can contact the remote domain


Thanks>>>>>
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Author Comment

by:solution786
ID: 24263484
We are using CA Etrust Antivirus software, no 3rd party disclaimer and no smart host. Can you send me steps needed to setup workstation with smtp installed  and to configure smtp connector with smart host.

Thanks
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Expert Comment

by:energeticbala18
ID: 24264227
if anitvirus is installed on the exchange server then set the exclusion for the folder Exchsrv, intepub, inetsrv
Also go to registry, take back up first, navigate to HKLM\current controlset\services\MSExchangeIS\virusscan and disable proactive scanning, background scanning

If we have xp client system then install SMTP service on the client system
then create SMTP connector with smart host of the client system IP (eg. [192.168.1.1])
go to address space tab and add the smtp address of the spefic domain to which we are not able to send emails
restart the SMTP services on exchange server
then all the email for that domains will be listed down on the smtp connector queue which you have created
if exchange is fine the email will be in the xp client (to check start-run-type logfiles ) or else the message will stuck in the exchange server queue

Thanks....

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Author Comment

by:solution786
ID: 24264772
I don't think antivirus is causing the problem because I disabled and stopped the antiviurs engine and even than I was not able to send email to that particular domain.
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Expert Comment

by:energeticbala18
ID: 24271918
did tried to configure the SMTP server ?
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Author Comment

by:solution786
ID: 24282865
I will appreicate if you can walk me through the steps to configure SMTP server.

Thanks
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Expert Comment

by:Mestha
ID: 24290324
You don't configure the SMTP server outside of Exchange. Exchange should do everything for you.
The only setting that may have to be changed on the SMTP virtual server in Exchange is the FQDN field.
ESM, Servers, your server, Protocols, SMTP. Right click on the default SMTP VS and choose Properties, then Delivery and Advanced. The FQDN field should match how your server is known on the internet - mail.example.com - however if that wasn't set correctly I would expect a lot more sites to reject your email.

Simon.
0
 

Author Comment

by:solution786
ID: 24290399
Simon,
I checked the FQDN field on the ESM and it is set correctly to mail.mydomain.ca.
0
 

Author Comment

by:solution786
ID: 24295838
I created SMTP connector with smart host of a client  XP system and the email to ncgames.com.br domain is not stuck in the Exchange Server queue. However I also don't see the email in the xp client queue also (on the xp client I went to start -->Run-->logfiles).

Thanks
0
 
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Expert Comment

by:energeticbala18
ID: 24297435
so did you verified whether the recepient received the message?
0
 

Author Comment

by:solution786
ID: 24298049
The recepient haven't replied me back yet. I am stll waiting for their reponse.
0
 

Expert Comment

by:cokemit
ID: 25664006
This just started happening last monday 10-19-09 that our emails to ncgames.com.br will not leave exchange. I tried telneting in, which seems I can get in to the blinking cursor, but the second I hit a key it kicks me out.
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Expert Comment

by:cokemit
ID: 25664339
Got it, it was an Open DNS issue blocking thier hosted mail server.
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