In my environment, I have a Primary site Server (Management Point, Distribution Point and Windows Updates Management Point Roles) and another Management Point (Management Point, Distribution Point and Windows Updates Point Roles) in an untrusted forest (Test Environment). Both forest are physically linked together with a Firewall between them. Firewall has been configured to allow communication between the Primary site Server and the Domain Controller in the other forest and also between the Primary site Server and the outside Management Point (Port list provided here https://technet.microsoft.com/en-us/library/hh427328.aspx).

Everything works fine except that I receive every x minutes (every 5-30 minutes) hundreds of Event error 10009 on the Primary site Server. After some days I have more than 50'000 errors !

Any help would be greatly appreciated.

And what does 10009 tell? 

Something like that:

Event Type:        Error
Event Source:    DCOM|
Event Category:                None
Event ID:              10009
Date:                     2015-3-26
Time:                     10:02:07
User:                     N/A
Computer:          <Computer Name>
Description:
DCOM was unable to communicate with the computer <Target Computer Name>

I think it's related to Component Summarization but not sure, because nothing is wrong in all SCCM Logs (no errors found)and everything is green in Site Status.

This might be worth a read.

http://blogs.msdn.com/b/asiatech/archive/2010/03/16/how-to-troubleshoot-dcom-10009-error-logged-in-system-event.aspx

Thanks for your answer and the link you provided.

As mentioned, everything works except that specific error in Eventlog (under System). Packages are distributed remotely (therefore is port 135 open). Comunication between forest works and Reporting works too. In Site Status of Primary Site (All Messages) I see when a Computer installs Software, TS (and so on) in the untrusted forest.

What's the Problem?

Find out what's happening at the same time in ConfigMgr (e.g. discovery or something like that). 

For example if I reset Counts on untrusted Forest Components, that error is thrown. But nothing in SCCM Logs nor Security eventlog on both Servers nor Security eventlog on DC

Any idea?

Yes, I know this is an old post, but Im trying to clean them up. Did you solve this problem, if so what was the solution?

Since no one has answer this post, I recommend opening  a support case with Microsoft Customer Support Services (CSS) as they can work with you to solve this problem.

Problem not solved, but not tested it with SCCM 2012 R2 SP1.

• Edited by Gaëtan Hermann Friday, August 14, 2015 8:03 PM

Problem not solved, but not tested it with SCCM 2012 R2 SP1.

• Edited by Gaëtan Hermann 11 hours 47 minutes ago

Problem not solved, but not tested it with SCCM 2012 R2 SP1.

At this point I recommend that you contact CSS directly for support. They will work with you to solve this problem.