This tool can adjust 3 "hidden" registry settings of
Internet Explorer to control caching of DNS records,
server connection timeout, and caching of server
information.

It can be useful to change these settings to very low
values, especially when testing web-servers with
quickly changing DNS records / IP addresses. For
example in DNS Round Robin or Simple Failover setups.

Internet Explorer does not honor and does not use the
TTL (time to live) value provided in DNS records.
Instead it caches all DNS records for a fixed period
of time (as per this setting) - with one exception:

After Internet Explorer has fetched a web-page, it
does not immediately close the TCP connection to the
web-server. By keeping the connection open, following
requests to the same web-server can be executed
faster. This is known as "keep alive".
This setting affects both DNS caching and server
connections ("keep alive") timeouts.

Internet Explorer does not refresh DNS records if
another page is requested from the same server domain
name within this time interval - even if the DNS
Cache Timeout setting has a lower value.
In other words, DNS records timeout according to the
higher value of this and the DNS Cache Timeout
setting.

However, server connections appear to timeout
according to the lower value of this and the Keep
Alive Timeout setting.

So for the most predictable results, the value of
this setting should be set lower than or equal to the
DNS Cache Timeout setting, and higher than or equal
to the Keep Alive Timeout setting.

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