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Cannot resolve names in top level domains like

I came across this the other day when trying to access a site that was in the top level domain .it, at first i just thought the site was down as other sites where working OK, but the site worked if I used my laptop which was accessing the net via 3g therefore different DNS servers, i then came across this article after a bit of searching KB968372

Essentially what happens is when the DNS server saves the NS record the TTL (Time To Live) for the A record is changed to be 1 day, But  TTL for the NS Record stays at 2 days. When the A record expires the DNS server starts returning SERVFAIL therefore it wont display the website.

Workarounds include restarting DNS, clearing the DNS cache, using DNS forwarders instead of root hints and setting maxcachettl to 2 days or greater, i wanted root hints to work correctly to stop ant problems with the isp DNS servers affecting our internet so i altered the maxcachettl settings.

1.    Start Registry Editor (regedit.exe).

2.    Locate the following registry key:

3.    HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\DNS\Parameters

4.    On the Edit menu, click New, click DWORD (32-bit) Value, and then add the following value:

  • Value: MaxCacheTTL
  • Data Type: DWORD
  • Data value: 0x2A300 (172800 seconds in decimal, or 2 days)

5.    Click OK.

6.    Quit Registry Editor.

7.    Restart the DNS Server service.

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