Thursday, 27 November 2014

Intermittent issue with Direct Access connection

I had this tricky problem on a customer site recently. Direct Access (Windows Server 2012 R2) worked perfectly most of the time but intermittently the Workplace Connection would just remain "Connecting" indefinitely. The logs showed that the connection failed with the following error:



This error was too generic to be useful and there was no pattern to this bizarre behaviour.

I eventually found the problem. ISATAP had not been removed from the Global Query Blocklist on one of the DNS servers.

Note that this is not an automatic process. It has to be done manually on all DNS servers. I removed ISATAP and restarted the DNS Server service.

Problem solved.


  1. I have inherited a Direct Access 2012 R2 server that actively serves approx 30-70 clients at any given time throughout the production day. I am running into a intermittent “connecting” issue with DA clients. DA will not be in a “connected” state. It simply says “connecting” and I can’t seem to find a rhyme, reason, nor a common denominator. Then all of a sudden DA will connect with either a restart or time. Random clients, random times. I have been reading that on domain controllers simply removing “isatap” from the GlobalQueryBlockList registry key should help resolve the issue I am experiencing. What are your thoughts?

    1. Yes Keith, that should work. You'll have to do this on all DNS servers that serve these clients.