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Emails from Yahoo not reaching my corporate server

Hi Everyone,

This email issue happens very intermittently but none the less, it has become quite the issue here at my workplace.

When a user sends an email from the yahoo domain, sometimes the email will not go through and they eventually receive an NDR.

Out of the 10 emails that are sent from my yahoo account to my corporate account, I received 9 of them with 1 email being returned with the message below.

Yahoo says that are investigating it but its been over a month and I haven't heard back from them.

Any idea how to resolve this issue?


"From: MAILER-DAEMON@yahoo.com <MAILER-DAEMON@yahoo.com>
Subject: Failure Notice
To: xxx@yahoo.com
Received: Wednesday, January 9, 2013, 2:42 PM


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

<xxx@simex.ca>:
Mail server for "simex.ca" unreachable for too long

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

Received: from [98.139.212.145] by nm16.bullet.mail.bf1.yahoo.com with NNFMP; 04 Jan 2013 15:30:57 -0000
Received: from [98.139.173.191] by tm2.bullet.mail.bf1.yahoo.com with NNFMP; 04 Jan 2013 15:30:56 -0000
Received: from [127.0.0.1] by smtp118-mob.biz.mail.bf1.yahoo.com with NNFMP; 04 Jan 2013 15:30:56 -0000
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yahoo.com; s=s1024; t=1357313456; bh=a0tPsQCtTPD7G4BLu1JoV6fPkLsDmRlxuJ8uG4vsKEQ=; h=X-Yahoo-Newman-Id:X-Yahoo-Newman-Property:X-YMail-OSG:X-Yahoo-SMTP:Received:Content-Type:Content-Transfer-Encoding:From:Message-Id:Date:To:Mime-Version:X-Mailer; b=BAfdfQbhPqAm3c/4w5A1YPwmNZp7JCGgYycMxk1wfvTYMe2tIr4SGDUgkX9lhElFGKH/eph+V6kNjbRq6M/Myx+Fnqz1G1aL+UIhRqHEv9v5fPsjh/PVTfE/Bxc+QxE+SM0rEWuyM7tXfNELVWaZi+tn+XuPYOkdVzF8LemUsBU=
X-Yahoo-Newman-Id: 721565.8518.bm@smtp118-mob.biz.mail.bf1.yahoo.com
X-Yahoo-Newman-Property: ymail-3
X-YMail-OSG: 4m6RgDkVM1mkPE3319MsBf6M1VsyhZUnUjIum.vvJ4pRkKa
M4GpxKbDHAjAUFOZUw4Pauv56yMOqHLvsEAfvg0J7f6tViLBOBueNBaIW1QU
yz5Q2ntQlw788mvDA8Fk3d01GKhf.SxTBQ1KESKrAS4A4oMpsWAFgs02LEV3
bGIOLlWzj_nReO0SZ3.BqOgTUC76cyjWt7za54uF64IqYmMY.pEZf1xN40Qe
WidkWK.VmrgmFYcVmrYM1rF7URSsdirO.wKaFXZOQmRrNSjTDbWNccT2MqAI
YgvROvV_IaiCRfzj_Df5YpYqqOHFpZFOj.uiko3EUyV_A_TGSQU.XmmVvmXb
.5I_1JntT6G4V_iokIZduPq2O7KhC0AgD8KNCJ38ErwdrltAb4mxXHekJCxg
h5e3Wk1afKn6x9lIEWpgCRsapHJMCrHrO4AJAZW8mn3gps8VA7oyQhiLzAaM
TeEqk
X-Yahoo-SMTP: 0rDW7UaswBAYy1Js.MkL6tK4z3CPi673uSs-
Received: from [10.0.0.72] (xxx@216.191.157.78 with xymcookie)
        by smtp118-mob.biz.mail.bf1.yahoo.com with SMTP; 04 Jan 2013 07:30:56 -0800 PST
Content-Type: multipart/mixed; boundary=Apple-Mail-DA89A6F7-A037-4463-B233-3E91C9FFABF4
Content-Transfer-Encoding: 7bit
From: JN<xxx@yahoo.com>
Message-Id: <43D14D74-C3EC-40E2-A0E4-455867DB0237@yahoo.com>
Date: Fri, 4 Jan 2013 10:30:45 -0500
To: John Nguyen <xxx@simex.ca>
Mime-Version: 1.0 (1.0)
X-Mailer: iPhone Mail (10A403)
0
jnsimex
Asked:
jnsimex
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3 Solutions
 
TheBDPSr. Sys EngineerCommented:
Just doing some inital tests. Looks like you have some reverse DNS issues I'd probably start there:


http://mxtoolbox.com/SuperTool.aspx?action=mx%3asimex.ca#


Appears you have some Transaction log processing issues as well.


**Also are you using any type of spam filtering software/hosting?
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Chris HInfrastructure ManagerCommented:
Are you using an SMTP proxy of any kind?

220 sim-svr-002.simex.ca Microsoft ESMTP MAIL Service ready at Mon, 21 Jan 2013 15:48:15 -0500

Test      Result      Hide

      SMTP Reverse Banner Check      OK - 216.191.157.78 resolves to mail.simex.ca
      SMTP Reverse DNS Mismatch      Warning - Reverse DNS does not match SMTP Banner      Ignore

      SMTP TLS      OK - Supports TLS.      
      SMTP Connection Time      0 seconds - Good on Connection time      
      SMTP Open Relay      OK - Not an open relay.      
      SMTP Transaction Time      5.320 seconds - Warning on Transaction Time      Ignore

Could by one of yahoo's qmail servers doesn't like you not having a correct reverse pointer record for your mail server(s)....
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Gary ColtharpSr. Systems EngineerCommented:
What kind of volume does your server do? I am showing only one MX record for that domain.
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jnsimexAuthor Commented:
@TheBDP - Can you elaborate on the reveres DNS issue? the IP 216.191.157.78 should resolve to the mx record mail.simex.ca. Yes, we use GFI Antispam for Exchange but the yahoo emails that are not delivered, do not even make it to the exchange server at all.

@choward16980 - No SMTP Proxy. Would changing the name in the banner from sim-svr-002.simex.ca to mail.simex.ca fix the SMTP reverse DNS mismatch?

@gcoltharp - I am not sure on the volume but we are a small to medium size company with about 50 mailboxes on a dedicated exchange server.
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Gary ColtharpSr. Systems EngineerCommented:
Changing the name in the server would correct the banner mismatch. Your reverse record is correct.
What version of Exchange? Have you looked at the queues to see how busy it is? If you are running GFI locally, then your server is responsible for cleaning the spam as well as processing the good mail.

Using an appliance or a hosted service for this would be better. A hosted service will also give you more than one MX record and some backhaul if your server is unavailable. A couple of hosted solutions are Three Lock, Appriver, Postini or ContentCatcher.
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jnsimexAuthor Commented:
@gcoltharp - I made the change to the SMTP banner and it passes the Reverse DNS mismatch now.

We are running Microsoft Exchange Server 2007 SP3. I check the queues now and then and it is always empty. The only time I saw emails in the queue was when we did a fairly large email mail merge . GFI is installed on the exchange server. At this point, I am not totally convinced that GFI plays a role because I have seen an email that was sent from a yahoo address to 2 simex addresses and 1 was deliverable while the other was not. It returned with the same NDR message "<xxx@simex.ca>:
Mail server for "simex.ca" unreachable for too long".


 SMTP Reverse Banner Check OK - 216.191.157.78 resolves to mail.simex.ca  
 SMTP Reverse DNS Mismatch OK - Reverse DNS matches SMTP Banner  
 SMTP TLS OK - Supports TLS.  
 SMTP Connection Time 0 seconds - Good on Connection time  
 SMTP Open Relay OK - Not an open relay.  
 SMTP Transaction Time 5.320 seconds - Warning on Transaction Time
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Gary ColtharpSr. Systems EngineerCommented:
That transaction time is very high.... an SMTP conversation (assuming no large attachment payload) should be extremely short.
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jnsimexAuthor Commented:
@gcoltharp - I found this link which fixed my high SMTP transaction time.

http://community.mxtoolbox.com/forums/viewtopic.php?f=6&t=13698

 SMTP Reverse Banner Check OK - 216.191.157.78 resolves to mail.simex.ca
 SMTP Reverse DNS Mismatch OK - Reverse DNS matches SMTP Banner
 SMTP TLS OK - Supports TLS.
 SMTP Connection Time 0 seconds - Good on Connection time
 SMTP Open Relay OK - Not an open relay.
 SMTP Transaction Time 0.312 seconds - Good on Transaction Time
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Chris HInfrastructure ManagerCommented:
I had an issue like this where the sending user had a known spyware URL in their signature and it was inadvertently blocked on my firewall.  Any commonalities in the blocked emails or are they all test emails?
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jnsimexAuthor Commented:
The test emails had an empty body. Only the subject line was modified to distinguish between the test emails.

I took a lot at the other emails that were never delivered and I do not see any commonalities between them.
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Chris HInfrastructure ManagerCommented:
Are there any entries in your SMTP inbound logs on your exchange server correlating with the receiving/blocking of these emails?  If not, this is an issue for yahoo.  If so, we can work forward with this information.
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jnsimexAuthor Commented:
@choward16980 - I did not have SMTP logging enabled, I just turned it on now on the receive connectors.
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Chris HInfrastructure ManagerCommented:
Cool.  Now you need to replicate the issue.  What this will tell us:

1.  If you see the SMTP session logged while one of the emails is blocked, then the problem points to your email server.

2.  If you don't see a SMTP session logged and the email was blocked, then yahoo has issues that are out of your hands.
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jnsimexAuthor Commented:
It seems to be working now but I will keep an eye on it. Thank you for your help.
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