Data type


Default value


0x0 | 0x1–0xFFFFFFFF seconds

0x15180 (86,400 seconds = 1 day)


Determines how long the Domain Name System (DNS) server can save a record of a recursive name query.

If the value of this entry is 0x0, the DNS server does not save any records.

The DNS server saves the records of recursive name queries in a memory cache so that it can respond quickly to new queries for the same name. Records are deleted from the cache periodically to keep the cache content current. The interval during which the records remain in the cache usually is determined by the value of the Time to Live (TTL) field in the record. MaxCacheTtl establishes the maximum time that records can remain in the cache. The DNS server deletes records from the cache when the value of this entry expires, even if the value of the TTL field in the record is greater.

Change method

To change the value of this entry, use Dnscmd.exe, a tool included with the Windows 2000 Support Tools. The change is effective immediately; you do not have to restart the DNS server.

Activation method

DNS reads its registry entries only when it starts. If you change the value of this entry by editing the registry, the changes are not effective until you restart the DNS server.

Note Image Note

This entry does not affect Windows Internet Name Service (WINS) data saved in the DNS memory cache. WINS data is saved until the Cache Timeout Value on the WINS record expires. To view or change the Cache Timeout Value on the WINS record, use the DNS snap-in. Right-click a zone name, click Properties, click the WINS tab, and then click the Advanced button.

Windows 2000 does not add this entry to the registry. You can add it by editing the registry or by using a program that edits the registry.