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SMTPDiag Error 250

OK everyone, I need help.

When sending an email, we are receiving an NDR back. I have confirmed that the email is good by sending to different email accounts on different networks. My feeling is that we are being blocked by the receiving side. But I am worried that either my firewall or exchange filters could be causing this.

I ran SMTPdiag and here is the results from that test

Searching for Exchange external DNS settings.
Computer name is CVSCALLAP.

Checking SOA for culaneenergycorp.com.
Checking external DNS servers.
Checking internal DNS servers.
SOA serial number match: Passed.

Checking local domain records.
Checking MX records using TCP: mccrums.ab.ca.
Checking MX records using UDP: mccrums.ab.ca.
Both TCP and UDP queries succeeded. Local DNS test passed.

Checking remote domain records.
Checking MX records using TCP: culaneenergycorp.com.
Checking MX records using UDP: culaneenergycorp.com.
Both TCP and UDP queries succeeded. Remote DNS test passed.

Checking MX servers listed for @culaneenergycorp.com.
Connecting to mix.twistedpair.ca [] on port 25.
Error: Expected "250". Server rejected the recipient address.
Failed to submit mail to mix.twistedpair.ca.

Im sure I have not included enough informtion for you to help. But this is a start.


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1 Solution
Out of curiosity, do you have a PTR record for the system that will be sending the mail?
It would help more if you posted what was the NDR that the users get when they send an email message. This usually gives more of an idea about the cause of the problem.

If your domain is mccrums.ab.ca then the DNS report shows up some interesting points...

You are announcing yourself as an invalid host...

mail.mccrums.ab.ca claims to be non-existent host mccal2.MCCRUMS.LOCAL:
220 mccal2.MCCRUMS.LOCAL Microsoft ESMTP MAIL Service, Version: 6.0.3790.1830 ready at Tue, 21 Feb 2006 16:41:32 -0700

and your reverse DNS points to an IP address with Shaw Cable.

Those two facts alone would be enough for some sites to reject your connection.

ssiimmpplleeAuthor Commented:
Sorry for not responding. I have been running around to other clients all day. The DNS report does show some interesting info. For example

"" FAIL All nameservers respond ERROR: Some of your nameservers listed at the parent nameservers did not respond. The ones that did not respond are:

Note: If you are running a Watchguard Firebox with DNS Proxy enabled, there may be a bug causing port numbers get mixed up -- if this is the case, you can contact Watchguard to see if they have a fix. ""

The client is infact running a Watchguard Firebox. I will need to confirm if the DNS proxy is enabled.

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

Subject: test: please reply
Sent: 21/02/2006 11:24 AM

The following recipient(s) could not be reached:

  'dstaus@culaneenergycorp.com' on 2/21/2006 11:24 AM
  There was a SMTP communication problem with the recipient's email server. Please contact your system administrator.
  <mccal2.MCCRUMS.LOCAL #5.5.0 smtp;554 Service unavailable; Client host [] blocked using dul.dnsbl.sorbs.net; Dynamic IP Addresses See: http://www.sorbs.net/lookup.shtml?

I will check these facts tomorrow.
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This is the problem:

blocked using dul.dnsbl.sorbs.net; Dynamic IP Addresses See: http://www.sorbs.net/lookup.shtml?

The remote site is using the SORBS dial up list. You can make all the changes you like but you will never be able to deliver email directly to that site.

You will need to setup an SMTP Connector to route email through your ISPs SMTP server.

It will not do any harm to get the server announcing itself correctly though.


I agree with Sembee regarding the information is in the NDR as well as the solution.
ssiimmpplleeAuthor Commented:
I setup the SMTP connector to get up and running.

It turns out that Telus has not created a reverse DNS for us which is why SORBS black listed us. So now I am off to have this corrected. I will also clean up the rest of our DNS while I'm at it.

Thanks for you help.

Cool...so it goes back the the PTR record being needed.
ssiimmpplleeAuthor Commented:
Ah shoot. Sorry flyguybob. It does go back to that. I should have shared this one.
That does not bother me on bit...I am glad that you got it solved.
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