Starting with vSphere 6.0, vCenter Server supports connection between vCenter Server and vCenter Server components by either IPv4 or IPv6 addresses.

Mixed IPv4 and IPv6 environment is not supported. When you install vCenter Server in an IPv6 environment, use the fully qualified domain name (FQDN) or host name of the machine on which you install vCenter Server. For pure IPv4 environment, the best practice is to use the fully qualified domain name (FQDN) or host name of the machine on which you install vCenter Server, because the IP address can change if assigned by DHCP.