The Internet Explorer and Firefox agents provide the capability to map a hostname to a specified IP address. This feature results in the agent bypassing the DNS lookup for a host; instead, it attempts to connect directly to the specified IP address.
The mapping can be to either an IPv4 or IPv6 address. IPv6 mappings only work on dual-stacked IPv6-enabled nodes.
When more than one IP address is provided, the agent attempts to connect to the first IP address on the list; if a connection cannot be made, it moves down the list of IP addresses in sequential order until it can successfully connect to one. If it cannot connect to any of the addresses provided, the agent reports a connection failure.
By default, the Recorder enables a user to provide up to three potential IP addresses as a destination. If a use case requires more than three destination IP addresses, additional mappings with the same origin host can be added to expand the destination list.
This feature can be used if you want to target a web monitoring test to a specific web server within a server farm, without creating new scripts. You can copy an existing test and add the host to the IP mapping.