As discussed earlier in the "Factors Affecting DNS Caching" section, a lot of independent variables determine whether a particular browser request for a hostname makes a remote DNS request. There is a DNS specification (http://tools.ietf.org/html/rfc1034), but it gives clients flexibility in how the DNS cache works. I'll focus on Internet Explorer and Firefox on Microsoft Windows, since they are the most popular platforms.
The DNS cache on Microsoft Windows is managed by the DNS Client
service. You can view and flush the DNS Client service using the
ipconfig /displaydns ipconfig /flushdns
Rebooting also clears the DNS Client service cache. In addition to the DNS Client service, Internet Explorer and Firefox browsers have their own DNS caches. Restarting the browser clears the browser cache, but not the DNS Client service cache.
Internet Explorer's DNS cache is controlled by three registry
ServerInfoTimeOut, which can be created in
the following registry key:
There are two Microsoft Support articles describing how these settings affect the DNS cache. These articles report the following default values for these settings:
What's implied (but not explained very well) is that DNS server TTL values less than 30 minutes have ...