Series of IPv6 Improvements

Contact: Pouria Mousavizadeh Tehrani <pouria@FreeBSD.org>

For the past 6 months, I have worked on refreshing our IPv6 stack and implementing pending RFCs in our stack, and they are now available on CURRENT.

So far, I have added the support for:

  • RFC 9131 and RFC 9898 Section 3.9: Support for Gratuitous Neighbor Discovery (GRAND).

  • RFC 8781 (Section 5): Ability to have multiple PREF64 options.

  • RFC 4861 (Section 7.2.6 - 7.2.8): Support for delayed Neighbor Advertisement for both anycast and proxy addresses.

  • RFC 4191: Support for Route Information option in Router Advertisement.

  • Removed the support for DRAFT_IETF_6MAN_IPV6ONLY_FLAG to replace it with RFC 8925.

Ongoing works:

  • RFC 8925: IPv6-Only Preferred Option For DHCPv4 (D56637)

  • RFC 4429: Add support for Optimistic DAD. (D55229)

I want to specially thanks Gleb Smirnoff for his timeless guidance and help on these works.

Last modified on: July 23, 2026 by Pouria Mousavizadeh Tehrani