IP operation will be enabled as specified in the following flowchart:
If IPv4-only operation is enabled, any IPv6 address(es) configured as parameter values will be ignored, and the next IPv4 address (if any) in a list of addresses will be used. If the parameter value does not contain any IPv4 addresses, the value will be treated as if it was null.
If IPv6-only operation is enabled, any IPv4 address(es) configured as parameter values will be ignored, and the next IPv6 address (if any) in a list of addresses will be used. If the parameter value does not contain any IPv6 addresses, the value will be treated as if it was null.
If dual-stack operation is enabled, whether IPv4 or IPv6 is to be used to contact a server is determined by the value of the parameter that contains the server address(es).
Rationale:
Dual-stack operation is required for endpoints by Requirement 1 of UCR 2008 [7.8-1d]. However, IPv6 must be disabled until it is deliberately enabled.