OpsMgr R2 discovery issue

This issue happened to me at a customers site. When pushing OpsMgr Agents to newly managed systems using the Discovery Method ‘Browse for, or type-in computer names’ this error message popped up:

First I thought there were some issues with the servers being discovered, like some needed services being turned off on the servers which need to be discovered, or not using the appropriate permissions. Or perhaps some ports were blocked? So I used Kevin Holman’s posting as a trouble shooting guide. Also this posting of him is a great help.

So I started to research the issue. But all seemed to be well: no blocked network ports, no authorization issues nor any needed service being turned off. Then a network sniffer on the Management Server was installed in order to see whether any network traffic was generated at all when running the above mentioned discovery.

No. Nothing! Yes, there was much traffic going on but not the discovery traffic flowing from the Management Server to the server which needed to be discovered. Not one packet what so ever!

Even more puzzling was the fact that the discovery of most servers residing in the same domain as the OpsMgr servers went without any problem what so ever. And for some other servers, residing in the same domain, the same error message popped up, while these servers are configured exactly the same…

Finally I decided to use the LDAP queries as a discovery method (Scan Active Directory) and that worked.

But it still puzzled me so I contacted Kevin Holman. He advised me to (un)check (*) the option ‘Verify discovered computers can be contacted’ in the ‘Auto or Advanced’ screen.

(*: When the Discovery doesn’t run with this option checked, uncheck it. And the other way round)

Tried it today, and yes, it works. I might be missing something here but it seems a bit like a bug.

So whenever Discoveries aren’t working as they should AND all is in place (checkout the earlier mentioned blog postings of Kevin), try the (un)check ‘Verify discovered computers can be contacted’ method and all should be OK now.

All credits go to Kevin. Thanks man!