Exchange 2010 not accepting emails from yahoo address

Hi there

Strange problem, our Exchange server appears to be rejecting emails from yahoo after they have been through our anti-spam provider.  This only seems to happen with yahoo address.  Even more strangely we have multiple accepts domains with many users having multiple aliases, I've sent a test email to myself from a yahoo account and it has delivered to one domain but not another.  I also included my gmail account which delivered no problem.

Failure notice as follows:

Sorry, we were unable to deliver your message to the following address.

Remote host said: 550 Not accepted. [BODY]

--- Below this line is a copy of the message.

Received: from [] by with NNFMP; 05 Dec 2011 17:03:16 -0000
Received: from [] by with NNFMP; 05 Dec 2011 17:03:16 -0000
Received: from [] by with NNFMP; 05 Dec 2011 17:03:16 -0000
X-Yahoo-Newman-Property: ymail-3
Received: (qmail 18138 invoked by uid 60001); 5 Dec 2011 17:03:15 -0000
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;; s=s1024; t=1323104595; bh=rmj+TcPW/MYtQW9tXokSDaxYgmB2363WHRQS+MdvpfM=; h=X-YMail-OSG:Received:X-Mailer:Message-ID:Date:From:Reply-To:Subject:To:MIME-Version:Content-Type:Content-Transfer-Encoding; b=RcnKcfGA2aEvhMM5XDqiatmtddhUzoyu6yqax1EbYy+TBpz8r0xpm3X+jlq4DlkHjn+Of4MvveDJKDq79w4jmBpCivkCKOAlM86rIzgl/cqIJVpz5dSJ+zEddfU/wv6LP6Ud+i01IlNvkoat6knk9pbCHm5J6B8g+e4CMYkYpMk=
DomainKey-Signature:a=rsa-sha1; q=dns; c=nofws;
X-YMail-OSG: Wb8QwFEVM1kCPyIjwMxU0CEfWmYBrrWaC_RxAY2mlZjzXY9
Received: from [] by via HTTP; Mon, 05 Dec 2011 17:03:15 GMT
X-Mailer: YahooMailWebService/
Message-ID: <>
Date: Mon, 5 Dec 2011 17:03:15 +0000 (GMT)
From: User <>
Reply-To: User <>
Subject: Test this one
To: "" <>,
  "" <>,
  "" <>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: quoted-printable

Any ideas?

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Please check your domain or your sending domain is not blacklisted.

You can use the following website to check this at
JonDReesAuthor Commented:
This is a problem receiving not sending.  I can happily send to yahoo just not receive!
Please diagnose the SMTP connection using SMTPDIAG:

you can download the application from :

The command line syntex is smtpdiag "" "" /Verbose

Also run this:
smtpdiag "" "" /Verbose

Simulating traffic in both directions will give you the best idea of what is happening.

Please refer to my top link for examples

Please run this and post back with the results on why the message
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JonDReesAuthor Commented:
does this work for 2010 or is there an alternative?  only the downloads says requires 200 or 2003.
This also works for 2010 as all it does is diagnose an smtp connection.
JonDReesAuthor Commented:
Got the following:

C:\Program Files (x86)\SmtpDiag>SMTPDIAG "" "" /v

Searching for Exchange external DNS settings.
Computer name is WOODFORD.
VSI 1 has the following external DNS servers:
There are no external DNS servers configured.

Checking SOA for
Checking external DNS servers.
Checking internal DNS servers.

Checking TCP/UDP SOA serial number using DNS server [].
TCP test succeeded.
UDP test succeeded.
Serial number: 202

Checking TCP/UDP SOA serial number using DNS server [192.168.xx.xx].
TCP test succeeded.
UDP test succeeded.
Serial number: 202
SOA serial number match: Passed.

Checking local domain records.
Starting TCP and UDP DNS queries for the local domain. This test will try to
validate that DNS is set up correctly for inbound mail. This test can fail for
3 reasons.
    1) Local domain is not set up in DNS. Inbound mail cannot be routed to
local mailboxes.
    2) Firewall blocks TCP/UDP DNS queries. This will not affect inbound mail,
but will affect outbound mail.
    3) Internal DNS is unaware of external DNS settings. This is a valid
configuration for certain topologies.
Checking MX records using TCP:
  MX: (10)
  MX: (10)
  A: []
  A: []
Checking MX records using UDP:
  MX: (10)
  MX: (10)
  A: []
  A: []
Both TCP and UDP queries succeeded. Local DNS test passed.

Checking remote domain records.
Starting TCP and UDP DNS queries for the remote domain. This test will try to
validate that DNS is set up correctly for outbound mail. This test can fail for
3 reasons.
    1) Firewall blocks TCP/UDP queries which will block outbound mail. Windows
2000/NT Server requires TCP DNS queries. Windows Server 2003 will use UDP
queries first, then fall back to TCP queries.
    2) Internal DNS does not know how to query external domains. You must
either use an external DNS server or configure DNS server to query external
    3) Remote domain does not exist. Failure is expected.
Checking MX records using TCP:
  MX: (10)
  A: []
Checking MX records using UDP:
  MX: (10)
Both TCP and UDP queries succeeded. Remote DNS test passed.

Checking MX servers listed for
Connecting to [] on port 25.
220 Microsoft ESMTP MAIL Service ready at Tue, 6 Dec 2011 17
:04:13 +0000


Received: Hello []

mail from: <>

250 2.1.0 Sender OK

rcpt to: <>

250 2.1.5 Recipient OK


221 2.0.0 Service closing transmission channel

Successfully connected to

It was also successful in the other direction.

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JonDReesAuthor Commented:
No solution provided
Marc BarashPresidentCommented:
What was the status of this issue (if you remember)? I'm having the same weird issue - my users cannot receive email from select Yahoo accounts. This has not always been the case, they were happily receiving email from these Yahoo folks for quite some time until several weeks ago when it just "stopped". The Yahoo folks do not get an NDR or message of any kind, so as far as they're concerned, their emails are received. On our side (Exchange 2010/SBS 2011), we never receive the email.

So recently I've created my own test Yahoo account and surprisingly, my users are able to receive my test emails! This completely throws me for a loop. We do have an Untangle firewall w/ spam filtering in front of our Exchange server, so I've disabled the spam filter and no change. My users can receive my Yahoo tests, they still cannot receive the other folks.

We don't seem to be having this problem with other domains but the concern is this: if these Yahoo folks aren't getting NDRs, who's to say that other external domains aren't experiencing something similar - and we just don't know about it?

Anyone else out there, thoughts? ideas? Where do I look in the Exchange logs that perhaps I missed something obvious perhaps? I've tested with SMTPDiag in both directions and all tests are successful each time.
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