HOW TO: Modify Time to Live on Domain Name System Records

This article describes the steps to modify Time to Live (TTL) on Domain Name System (DNS) records. Time to Live is used by name servers and some DNS clients to determine the length of time that a name must be cached. In Windows 2000, the default TTL for DNS records is 60 minutes. You can modify the TTL of the record in the DNS Management console.

By default, the TTL field is not displayed on records. If you want the TTL field displayed on records, enable the Advanced View feature.

Modify the TTL on a Single Record

WARNING: If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.

1. In Administrative Tools, open the DNS Management console.
2. Click View.
3. Click to select the Advanced check box.
4. Right-click the record that you want to modify. The record displays a TTL field that you can modify.

Modify the Default TTL for an Entire Zone

1. In Administrative Tools, open the DNS Management console.
2. Click View.
3. Click to select the Advanced check box.
4. Right-click the zone that you want to modify. The zone record displays a Minimum Default Zone TTL field that you can modify. The default for a new zone is 60 minutes.

The caching of records on a host is further controlled by the caching resolver service.

Control the Caching Time on a Client Computer

1. Start Registry Editor (Regedt32.exe).
2. Locate and click the following key in the registry:
   HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Dnscache\Parameters
3. On the Edit menu, click Add Value, and then add the following registry value:
   Value name: MaxCacheEntryTtlLimit
   Data type: REG_DWORD
   Radix:
   Value data: 0x1-0xFFFFFFFF (seconds)
4. Quit Registry Editor.