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Why will Exchange 2007 not deliver to this address

I have a user that always get this notification when emailing to the address listed. He can send email to this address without problem from his gmail accaount. Please Advise.

Delivery is delayed to these recipients or distribution lists:

contato@grupoconecta.com.br

Subject: flow-rite valves

This message has not yet been delivered. Microsoft Exchange will continue to try delivering the message on your behalf.

Delivery of this message will be attempted until 8/27/2010 10:58:15 AM (GMT-05:00) Eastern Time (US & Canada). Microsoft Exchange will notify you if the message can't be delivered by that time.
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Johne75
Asked:
Johne75
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1 Solution
 
endital1097Commented:
perform an nslookup from the exchange server for the mx record of that domain
nslookup
set type=mx
grupoconecta.com.br

then attempt to connect to the server on port 25
telnet mx.grupoconecta.com.br 25
ehlo yourdomain.com
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CompanionCubeCommented:
Please take a look in the Exchange queues.

Also try the "telnet test" from your Exchange server:
http://support.microsoft.com/kb/153119
and let us know the results.

did you get "4.7.1 Client host rejected: cannot find your hostname"?
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Alan HardistyCommented:
I can't connect to their server via Telnet!  Possibly a config issue with their server.
What is your domain name and IP address - I will check that you are configured properly (and I will obscure / hide / delete the domain name and IP address once you post it).
Alan
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Johne75Author Commented:
Alan,
IP for exchange? And not sure if I am comfortable giving that info out? Isnt that a security concern? I am not familiar with Telnet.
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Alan HardistyCommented:
If you don't want to post the info (which I appreciate), you can email me at alan @ it-eye.co.uk.
I am a Zone Advisor and can hide / delete / modify your comments, so the info mwould not be made publicly available once I have obscured it.
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endital1097Commented:
jsut use the commands from my earlier post
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Alan HardistyCommented:
I have tried telnet and it fails.
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Johne75Author Commented:
I tried the telnet too it failed. nslookup worked fine
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CompanionCubeCommented:
please post the failure code
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endital1097Commented:
I think the issue is on their end
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Johne75Author Commented:
Telnet mx.grupoconecta.com.br 25 error:
450 4.7.1 Client host rejected: cannot find your hostname, [216.120.xxx.xxx]

Telnet mx.grupoconecta.com.br error:
Connecting To mx.grupoconecta.com.br...Could not open connection to the host, on
port 23: Connect failed
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endital1097Commented:
they are blocking you
make sure you are not on any block lists
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Johne75Author Commented:
OK so because we cant telnet to them we are blocked somehow on there end. As I am not familiar with telnet other than what I just googled and experienced here, I am curious to understand how telneting determines that. Can you explain briefly and I shall close this question. Thanks Everyone for all your help.
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Alan HardistyCommented:
You have an MX record with a Priority of 0 - some mail server cannot work with this priority record. Please change it to anyting other than 0.
Your Reverse DNS is configured as flowrite01.yourdomain.com yet your mail server is configured as mail.yourdomain.com - they need to match.
mail.yourdomain.com resolves happily to your IP Address - so that is good.
You are also listed on Backscatterer.org (a blacklist) :
http://www.mxtoolbox.com/SuperTool.aspx?action=blacklist%3a216.120.xxx.xxxBackscatterer.org lists servers that send Non-Delivery reports to spammers. You need to configure your server to filter recipients not on yur server to cure this.
Please issue the following command from the Exchange Management Shell:
Set-RecipientFilterConfig -RecipientValidationEnabled:$true



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CompanionCubeCommented:
when you telnet via port 25 to the other email server, you can see the response from the other email server; if the response is an error, such as "Client host rejected: cannot find your hostname" you can act accordingly; this would be the error your exchange server is getting from the remote email server
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endital1097Commented:
@alan - you have the advantage here of knowing additional info :)
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Alan HardistyCommented:
The info was posted for all to see.
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Alan HardistyCommented:
http:#a33628740 posted the IP address which I only just obscured.
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Johne75Author Commented:
Alan,
DNS is my week spot as I havent worked with it since my formal training 3 years ago. I can not find on our domain controller in DNS the MX record or reverse DNS you mention. Can you advise.
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Alan HardistyCommented:
Reverse DNS is setup via your ISP - you need to call them and ask them to change it for you.
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Johne75Author Commented:
Ah I see. I found the MX record the priority is set to 10 not 0 ?
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Alan HardistyCommented:
Yep - 10 is fine - anything other than 0 works ; )
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Alan HardistyCommented:
Have you run the Exchange Shell command I posted?
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Johne75Author Commented:
not yet also, you said priority was set to 0 in a previous post and it was not. Just wondering if this changes your recommendations based on it was already where it should be.....
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Alan HardistyCommented:
The MX priority will affect inbound - it won't affect outbound.  I am just being tidy : )
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Alan HardistyCommented:
Extract from www.dnsstuff.com for your domain (assuming I have the domain name correct):
Your 1 MX record is:

0 mail.your-domain.com. [TTL=3600] IP=216.120.xxx.xxx [TTL=3600] [US]
 
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Johne75Author Commented:
Alan,
I turned on the recipient validation. Sound like this will block a lot of spam before its even filtered by our Ninja Spam filter? Seems like the Spam filter should be doing that before it hits Exchange? I am waiting for my ISP to get back to me on the reverse DNS we have discussed it. The  mentioned flowrite01 is a long ago decomissioned server?
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Alan HardistyCommented:
I just sent a test message to "contato@grupoconecta.com.br" and it was just read.
This suggests that the problem is definitely at your end.
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Johne75Author Commented:
Alan,
If I complete your recomendations shouold this solve the problem?
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Johne75Author Commented:
Also, We use godaddy. I see our MX is 0 on godaddy but 10 on our DC. I am thouroughly confused now.
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Alan HardistyCommented:
Yes - the changes should make your situation much better.
Your MX records should only be on GoDaddy - there should not be an internal MX records as you should be relying on DNS externally to resolve things.
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