SBS 2008 DNS Problem - The answer

Friday, 06 March 2009 (510 days ago)

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If you're running Microsoft Small Business Server 2008 - AKA SBS 2008 - You may experience occasional internet problems resolving certain websites and domain names...

THe problem is caused by 'Root Hints' the method the server is using to resolve DNS requests.

There are several workarounds to the issue, these include restarting the DNS server service every few days (impractical), clearing the DNS cache (again not ideal), switching to DNS Frowarders (Resolves the DNS requests using your ISP's DNS servers) and setting maxcachettl cache to 2 days or greater...

To set the maxcachettl cache to 2 days or more, use the following:

1. Start Registry Editor (Regedit.exe)
2. Drill down to the following registry key - HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\DNS\Parameters
3. Right click in the right-hand window and select  New > DWORD (32-bit) Value then add give it the name MaxCacheTtl
4. Double click the new value and select 'Hexdecimal' the enter the value 0x2A300
5. Click OK
6. Quit Registry Editor.
7. Restart the DNS server service.

This should now resolve the intermitten DNS issue.