IPv6: Enable RFC 4429 Optimistic DAD

configname: CONFIG_IPV6_OPTIMISTIC_DAD

Linux Kernel Configuration
└─>Networking support
└─>Networking options
└─>The IPv6 protocol
└─>IPv6: Enable RFC 4429 Optimistic DAD
In linux kernel since version 2.6.22 (release Date: 2007-07-08)  
Support for optimistic Duplicate Address Detection. It allows for
autoconfigured addresses to be used more quickly.

If unsure, say N.