DCOM was unable to communicate with the computer using any of the configured protocols; requested by PID 1830 (C:\Windows\system32\dcdiag.exe).

This error and a couple of others to different IP addresses but referencing the same PID come up about once an hour. We are stumped as to why. No other domain controller is showing these errors.

I do see these IP addresses in HKLM\SYSTEM\CurrentControlSet\Services\DNS\Parameters, but I see them too in our other two domain controllers which aren't tossing this error.


  • 1
    Don't use Google DNS on your DC network adapter properties?
    – Greg Askew
    Jun 11 '15 at 19:35
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    Not using Google DNS on the router, and a couple of the other IP's have nothing to do with Google. Jun 11 '15 at 19:38
  • How is the router related to this?
    – Greg Askew
    Jun 11 '15 at 19:48
  • 1
    Run regedit and search for the ip address. Also check device manager for ghosted network adapters. From the command prompt: Set devmgr_show_nonpresent_devices=1, then run devmgmt.msc.
    – Greg Askew
    Jun 11 '15 at 19:58
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    This registry path stores configuration parameters for the DNS Server role. Is this DC also a DNS server? Do the offending IPs show up in your DNS configuration (e.g. on the Forwarders or Root Hints tabs)? Jun 12 '15 at 17:53

DCOM was unable to communicate with the computer using any of the configured protocols; requested by PID 1830 (C:\Windows\system32\dcdiag.exe)

It sounds like Wwindows is assuming your DNS Forwarder ( is a windows machine ... which it is not.

Is setup as a forwarder in DNS or actually configured on the NIC?

If your DNS servers are setup correctly (with forwarders on your DNS server), you do not need to add external DNS servers to your NIC configuration. Otherwise Windows appears to assume that your DNS servers configured on the NIC are other Windows servers and tries to connect via DCOM (e.g. not using DNS but the DCOM serialized objects)

A brief guide on setting up forwarders on your 2012 DNS server

On a side note, it would be better to add your ISP DNS servers before on your forwarders, unless your ISP services exhibit higher latency in lookup times. Generally the DNS queries will be dominated by the RTT of your network, so the closer the better. But you will need verify with testing first.

  • I snot on the NIC card, nor is it to be found in the DNS configuration. The only place it is found is in the registry location I mentioned above. Our other two domain controllers have this same information in their registry but do not show this error. Jun 15 '15 at 13:55
  • Why don't you amend your question with the actual registry entry you are concerned about, otherwise we are all just guessing what is going on. Jun 16 '15 at 6:03
  • Read my question, the registry entry is listed there... HKLM\SYSTEM\CurrentControlSet\Services\DNS\Parameters Jun 16 '15 at 13:56
  • @WayneInYak: there are multiple entries under parameters, you didn't say which one. The other DCs don't show this error probably because dcdiag wasn't run on them. (your post suggested the DCOM error was triggered by dcdiag)
    – strongline
    Jun 18 '15 at 16:44
  • What is triggering dcdaig then? These error messages show up every hour on the server. Jun 18 '15 at 16:59

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