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Having trouble sending to some domains

Posted on 2011-03-25
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277 Views
Last Modified: 2012-05-11
We have SBS2008, which was migrated from SBS2003 and working fine for about a year. Outlook 2007 is the client and OWA has the same results. Recently, we are sending e-mail to some domains and they are not receiving them - most domains work fine. We are using our ISP as the Smart Host on Exchange, but even when we change to DNS, the e-mail doesn't get there. I've turned on logging and the logs show that the e-mail was sent. There is nothing in the SMTP queue.

We are not showing up on any blacklists.

We are also using GFI to add a disclaimer to the end of every e-mail.

What tools can I use to troubleshoot this?
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Question by:notacomputergeek
15 Comments
 
LVL 10

Expert Comment

by:Hutch_77
ID: 35216104
Telnet is the best I can think of in combination with MX toolbox to get all the information of the other domain
Telnet into their mailserver on port 25 and see if it lets you pass an email through manually.

If it does not reject then you are looking at a DNS issue somewhere
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LVL 12

Expert Comment

by:FDiskWizard
ID: 35216360
Never assume the other side knows what they're saying. "Not getting the email" can mean a lot of things. I've had many companies block us because our email passes through our parent company outside of the US.

Besides TELNET host 25, there is a small utility called Bmail.exe that is easier to use. You just provide Subject, etc.... and I would suggest using the -H option to force headers.
If there is an error talking to the server, it will show you on the command line.

Run either from your actual mail server, so that you have the same scenario.


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LVL 42

Expert Comment

by:Amit
ID: 35216550
Check this link,

http://www.experts-exchange.com/Software/Server_Software/Email_Servers/Exchange/Q_26909143.html

There is a very good article from Alan. That can help you out.
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LVL 13

Author Comment

by:notacomputergeek
ID: 35218051
I can telnet into mail.mydomain.com and send a message and it is received. I have also configured another personal account using Microsoft Mail on a Windows XP computer to send with mail.mydomain.com and it is received. I can also log into my Smart Host webmail and send from there and it is received.

bmail will not install on my 64-bit server.

So, I think the problem is on my Exchange server. I know the Outlook client is communicating with the Exchange server, because I can see it in the SMTP logs. Once at the server it looks like it's been sent, but goes nowhere.
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Author Comment

by:notacomputergeek
ID: 35218113
Just to clarify, mail.mydomain.com is an AT&T server (Smart Host), not our Exchange server.
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Expert Comment

by:Hutch_77
ID: 35218136
I know what your problem is.

The clients are using your exchange server to send rather than the smart host, and because your MX records would point to that server it is being blocked.
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Expert Comment

by:Hutch_77
ID: 35218156
Doh hit submit to quick.

I had a client before that setup the Exchange to store email and imap or pop using a hosted solution.. Wh I didnt know but they wanted it that way.  Problem was when people would fiddle with outlook they would set their exchange to primary and it would then send all email using exchange which works great for internal and even for a lot of external until you get to a client that uses a spam protection or looks for proper MX records and you get this problem.  When they reply to it he address it goes to the hosted solution and this works and all internal email stays internal.  
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Author Comment

by:notacomputergeek
ID: 35218168
Not sure I follow. The clients' Outlook accounts are set up as an Exchange account and Exchange is set up to send through the Smart Host.

Can you elaborate on your answer?
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Expert Comment

by:Hutch_77
ID: 35218186
Ok I misunderstood.  I was under the impression that the clients hit the hosted email and stored in exchange.

Do you have an external account you can send emails to and see what happens?  do you have email sitting int he q's that are not releasing?

And the OWA is that a hosted OWA orr is that actually on your exchange server you tested from?
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LVL 13

Author Comment

by:notacomputergeek
ID: 35218231
This client is using POP and AT&T to host e-mail. I think it's mainly to not have their e-mail open to the whole world and let AT&T's servers filter alot of incoming junk. It also allows their company to function (e-mail-wise) if they lose connection to the internet or the server goes down.

What are the solutions?
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Author Comment

by:notacomputergeek
ID: 35218258
Yes, I have an external account I've been using for testing (2 actually at different domains). No e-mail in the queues, unless there's another place other than the Queue Viewer. Yes, OWA is our Exchange server.
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LVL 1

Expert Comment

by:vagedis23
ID: 35218262
Make sure your reverse dns record (PTR record) for your mail server is avaiable on the internet. Somers mail servers perform à reverse lookup when they receive an email from another mail server. The ip adres must be resolvable back to the same name your mail server has in your MX record.

If you do not host your dns yourself, talk to your ISP. They can create the PTR record for you

Good luck !
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Expert Comment

by:Hutch_77
ID: 35218294
ok I read webmail as OWA but that is a different service.  at this point I would talk with ATT and see if they made any changes.  

If it was working yesterday or a week ago and you made no changes then it should still work unless ATT mad e a change.  It appears the break is between your smarthost and your exchange server.
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Accepted Solution

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notacomputergeek earned 0 total points
ID: 35318579
I went ahead and reconfigured the server this weekend to receive e-mail directly and not use AT&T mail servers/POP3. Changed DNS and got AT&T to change rDNS PTR. I still had the same problem. E-mail was not being delivered to any @cox.net or domain hosted by Network Solutions. These are the ones I could verify. Talked to NS and they said our domain was blacklisted and would put in a request to unblock. I called COX and they apparently don't block domains, but the tech support offered to do some tests. After changing the SPAM setting in our COX account from "automatically delete" to "allow it, but mark as SPAM", a test e-mail came into the COX Inbox, but was tagged as SPAM. I did further tests to confirm this, but apparently the GFI disclaimer added to every one of our emails was causing it to be flagged as SPAM by some mail servers. I disabled the GFI disclaimer on the server and added the same disclaimer to my signature in Outlook and it was not detected as SPAM. Without talking to GFI, I can only assume that the HTML encoding on the disclaimer was triggering it as SPAM. Here is the disclaimer:
The information and any attachments contained in this email message may
be privileged, confidential, and protected by law from disclosure. If you are
not the intended recipient, any dissemination or copying is strictly prohibited
by federal law. If you think that you may have received this email message
in error, please notify the message sender at the email address above and
destroy this message.

Pretty staight forward, but causing a problem. What I don't know is why it's apparently worked for at least 6 months and now doesn't. It's possible companies have tightened up their mail servers due to excessive SPAM. All e-mail is flowing fine this morning, except for one @sbcglobal.net that was blocked. I contacted AT&T and they were able to unblock it.

I will wait to close this, in case there are further comments.

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Author Closing Comment

by:notacomputergeek
ID: 35372940
Discovered solution on my own.
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