Server 2012 R2, DNS Service:
In DNS Manager, what is the functional difference between "Scavenge Stale Resource Records" and "Clear Cache."?
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1 Answer
A DNS cache (sometimes called a DNS resolver cache) is a temporary database, maintained by a computer's operating system, that contains records of all recent visits and attempted visits to Web sites and other Internet domains. DNS Cache Poisoning
A DNS cache becomes poisoned (sometimes also called "polluted") when unauthorized domain names or IP addresses are inserted into it. Occasionally a cache may become corrupted due to technical glitches or administrative accidents, but DNS cache poisoning is typically associated with computer viruses or other network attacks that insert invalid DNS entries into the cache. This poisoning causes client requests to be redirected to the wrong destinations, usually malicious Web sites.
Flushing a DNS Cache
When troubleshooting cache poisoning or other Internet connectivity issues, a computer administrator may wish to flush (meaning clear, reset, or erase) a DNS cache. In Microsoft Windows, flush a DNS cache using the ipconfig tool as follows:
http://compnetworking.about.com/od/dns_domainnamesystem/f/what-is-a-dns-cache.htm
DNS scavenging refers to a technique used in DNS servers that allows the cleaning of outdated information used by the DNS server to find resources. This functionality is available in Windows DNS servers and helps automate the removal of obsolete records
The feature is integrated in DNS servers to facilitate the removal of old records that are no longer needed by the server. Failure to effectively delete the records leads to their accumulation, affecting the performance of the server. Apart from occupying disk space on the server, the outdated records may also be used to service user queries. It is therefore imperative that the records are updated dynamically. When a computer previously connected to a network losses the connection, its record needs to be removed from the server. The server administrator therefore needs to understand how to configure DNS scavenging correctly. He should always ensure that the feature is active for all zones. After enabling the feature, the refresh and no-refresh intervals should be set. These two values determine whether resource records are outdated or are still valid. If outdated, they need to be eliminated so that they are not retained in the server. The event log in the DNS server should be used to troubleshoot problems with DNS scavenging. https://www.reference.com/technology/dns-scavenging-6d189393d90c607c#
