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Domains unable to send to Comcast.net from Exchange servers

Posted by
Official Employee

Message 1 of 13
33,813 Views

We have recently seen a number of third party domains that cannot send to Comcast. This issue has been confirmed as being related to Microsoft Exchange servers. It appears internal DNS management within these mail severs are not correctly querying against our DNSSEC servers which has been brought to Microsoft’s attention. If the senders are receiving 400 4.4.7 Message Delayed or 451 4.4.0 DNS Query Failed errors they are more than likely affected, and should attempt the fix below.

 

Enabling the below check box in red has been seen to fix the problem. Other fixes are present which could be unique to the version of exchange and operating system installed such as putting the MX record in the hosts file.

 

Any senders who perform these alterations and still experience this problem should contact Microsoft for further assistance.

 

To enable ‘Use the external DNS lookup settings on the transport server’

In the Exchange Management Console (as seen in the below image)

1.  Open "Organization Configuration"

2.  Click "Hub Transport"

3.  Click "Send Connectors"

4.  Open the properties for "Internet Mail"

5.  Click the "Network" tab

6.  Check "Use the External DNS Lookup settings on the transport server"

7.  Reboot the server (important)

 

 

 

More information can be found at the Microsoft TechNet articles below:

http://social.technet.microsoft.com/Forums/en-US/exchangesvrtransport/thread/2e9a6263-7863-4d13-9480...

http://social.technet.microsoft.com/Forums/en-US/exchangesvrtransport/thread/a9b1a718-7b22-4678-aa91...

Severin
Comcast Anti-Abuse Manager


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12 REPLIES
Posted by
Visitor
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Message 2 of 13
33,410 Views

I find it interesting that Comcast is blaming this issue on Microsoft Exchange considering it is a recent issue and Exchange has been around for many years.  The latest version of Echange, 2010, was released in October 2009.  As an email administrator I can attest that of all of the many, many email domains that my users send messages to only Comcast and their DNS servers have this problem.  It's unfortunate that we must change our internal server configurations, that have worked for years and work for all other domains, to be able to send to comcast.net addresses.

Posted by
Official Employee

Message 3 of 13
33,384 Views

At this time it would be an issue fairly specific to delivering to Comcast since we are the first large ISP to launch a DNSSEC platform. I can assure you that many other large networks will be following this year as it has become an agreed-upon IETF specification. With the variety of DNS-based attack vectors it's become necessary. At least admin's will have this chance to adjust settings before it becomes an issue with the majority of their SMTP transmissions.

 

More information here:

http://customer.comcast.com/help-and-support/internet/domain-name-system-security-extensions/

http://en.wikipedia.org/wiki/Domain_Name_System_Security_Extensions

Severin
Comcast Anti-Abuse Manager


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Posted by
Visitor
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Message 4 of 13
26,169 Views

How do you perform this process in Exchange 2003?

Posted by
Regular Visitor
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Message 5 of 13
23,010 Views

What about non exchange outlook? Ihave issues now with 2010 and port problems with sending and receiving. I was talking to Yogi and would like to again about this. Outlook says email has gone out but it is not really sending the email. I have been dealing with this for 4 days.

Posted by
Official Employee

Message 6 of 13
22,973 Views

wetboyz,

 

Can you send me a private message with your email details (addresses you're sending from and to)? I can take a look into it.

 

Thanks

 

Private Messages (PM’s)

 

At the top of each Forum page you will see a small white envelope  

 

This is the icon for Private Messages, referred to as ‘PM’s’.  A Private Message is a way to communicate in private, to another User, Moderator, or Administrator out of public viewin the Forums.

 

 

The white envelope turns to yellow when you receive a PM.  

 

To open a PM to read it, double click on the yellow envelope. If you click on the white envelope a window will open with tabs for your Private Message Inbox, Sent Messages, Friends, Ignored Users, and Compose new Message.  You can also access this area by clicking on the Username in a Thread or post.  By default, Private Messages are enabled.  You can disable this feature in My Settings>Preferences> Private Messenger

 

Severin
Comcast Anti-Abuse Manager


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Official Employees are from multiple teams within Comcast: Product, Support, Leadership.
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Posted by
Visitor
Message 7 of 13
22,735 Views

Same problem hear with Exchange 2003.  Can you please just post the fix for the 2003 version of exchange.

Posted by
Frequent Visitor

Message 8 of 13
22,691 Views

I cant say thank you enough to Severin for fixing my problem.

After 4 days plus of dealing with other comcast "troubleshooters" or level 4 techs, he nailed it in one pvt message. I am glad I stumbled onto the forum and to Severin.

Posted by
Official Employee

Message 9 of 13
22,686 Views

danoz,

 

Unfortunately I could not find a full walk through on Microsoft's site, and I'm not too familiar with Exchange as an MTA personally. The two technet discussions I linked to in the original post do make mention of Exchange or Server 2003, perhaps they're a good launch point to troubleshooting your situation.

 

http://social.technet.microsoft.com/forums/en-US/exchangesvrsecuremessaginglegacy/thread/a9b1a718-7b...

http://social.technet.microsoft.com/forums/en-US/exchangesvrsecuremessaginglegacy/thread/2e9a6263-78...

Severin
Comcast Anti-Abuse Manager


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Community Icon
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We ask that you post publicly so people with similar questions may benefit.
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Please post so people with similar questions may benefit.
Was your question answered?
Mark it as a solution!solution Icon
Posted by
Visitor
  • Thank you contributor for your first reply to the community!
 Posting replies is the best way to get involved.

Message 10 of 13
20,080 Views

Hello CC_Severin,  I am runnin into same issue with my exchange 2010 server..we can't send to comcast.net addresses...we can receive but can't reply as well....

Posted by
Gold Problem Solver

Message 11 of 13
20,045 Views

I don't know if this clickable link will help you aty all, but thought I shouild post it for you.

 

http://www.rackspace.com/knowledge_center/article/manually-setting-up-outlook-2010-with-microsoft-ex...



Need Email Help? Please post the following information in your post.
Do you use XfinityConnect? The Full or Lite version?
Do you use an email client? Which one? (Eg; Windows Live mail, Outlook, a smartphone etc.)
Which browser/version do you use? And- have you cleared your browser cache?
Which operating system? XP, Vista, Windows 7, Mac OS X
Details of the problem you are having.




Posted by
Official Employee

Message 12 of 13
20,039 Views

chefred,

 

Just to ensure it's the same issue, can you send me a private message with the error details your server is seeing as well as its IP address? I want to be sure we identify the issue and help you accordingly.

 

Thanks!

 

Info on Private messages....

Private Messages (PM’s)

 

At the top of each Forum page you will see a small white envelope  

 

This is the icon for Private Messages, referred to as ‘PM’s’.  A Private Message is a way to communicate in private, to another User, Moderator, or Administrator out of public viewin the Forums.

 

 

The white envelope turns to yellow when you receive a PM.  

 

To open a PM to read it, double click on the yellow envelope. If you click on the white envelope a window will open with tabs for your Private Message Inbox, Sent Messages, Friends, Ignored Users, and Compose new Message.  You can also access this area by clicking on the Username in a Thread or post.  By default, Private Messages are enabled.  You can disable this feature in My Settings>Preferences> Private Messenger

 

Severin
Comcast Anti-Abuse Manager


Community Icon
I am an Official Comcast Employee.
Official Employees are from multiple teams within Comcast: Product, Support, Leadership.
We ask that you post publicly so people with similar questions may benefit from the conversation.

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Community Icon
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We ask that you post publicly so people with similar questions may benefit.
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Posted by
Official Employee

Message 13 of 13
13,997 Views