Archive: August, 2012

Troubleshooting slow logon/boot on Win7

No comments August 17th, 2012

As I mentioned earlier in a post, causes of slow logons can be many things and troubleshooting this is often time consuming. I recommend you to download the ADK tools for Win8 (for the moment it’s for the Consumer preview) and use the “Windows Performance Recorder” and “Windows Performance Analyzer” to help you find the culprit.

To get an overview of the tool and some examples, take a look at this excellent TechEd session: How many coffees can you drink while Windows 7 boots?



GPO to remove ISATAP blocking from DNS

1 comment August 6th, 2012

When you use DirectAccess (DA) you have to unblock ISATAP on your DNS servers, so when clients do a DNS lookup for ISATAP they will get an answer.

If you add a new domain controller with the DNS role, you must remember to remove ISATAP from the block list. You removed it on your DNS servers when you configured DA long time ago, but will you or your successor remember to remove the blocking if you add a new DC/DNS?

I didn’t until I saw a 7600 event id on the new DC/DNS…

Too see the current settings:

dnscmd /info /globalqueryblocklist

To remove ISATAP manually from the block list:

dnscmd /config /globalqueryblocklist wpad

To avoid this from happening in the future, I configured a Group Policy (GPO) to do the job. I reckon a GPO is more reliable than a Teflon brain.

Open the Group Policy Management consol.

Create the WMI:

First you need to create a WMI filter so the GPO only apply to servers with the DNS server role. Give it a meaningful name.

Query:  SELECT id FROM Win32_ServerFeature WHERE id = "13"

(ID 13 = DNS Server)

Create the GPO/GPP:

Group Policy Objects -> New

Give it a name. I called it “GPP_Unblock_ISATAP”.

Computer Configuration – Preferences – Windows Settings – Registry

Choose New – Registry Item

Action: Update

Path: HKLM\System\CurrentControlSet\Services\DNS\Parameters

Name: GlobalQueryBlockList

Value to remove: isatap

Link the GPO to the WMI filter you created:

Link the GPO to the OU where your DNS servers reside. I linked it to the Domain Controllers OU since we don’t have any standalone DNS servers. The WMI filter will anyway only apply to DNS servers, so you can link it higher up.

You’ll have to restart the DNS server service, or reboot the server before the setting is applied to the DNS server. Check the status “dnscmd /info /globalqueryblocklist”. If ISATAP is not present you are good to go.

Notice this only apply to Win2008 and newer, since legacy OS don’t have the Win32_ServerFeature class.

If you have Win2003 DNS servers, you’ll see that the WMI filter return “false” and the GPO will not apply:

On Win2008 and newer: