- tcp-bind-ipv6-onlyparameter
When #f, the default, IPv6 listening sockets will accept IPv6 or IPv4 connections when possible. This is only relevant when listening on the unspecified address "::". When #t, IPv6 listeners will not accept IPv4 connections.
This option is ignored when unsupported, such as on Windows 2000 and XP, whose IPv4 and IPv6 stacks are separate.