Apparently starting with version 20080615.2, dhcp6c refuses to run without a dhcp6cctlkey file. This patch generates one using dd, /dev/random and b64encode.
Created attachment 194716 [details] patch (Happy to commit with maintainer approval.)
Created attachment 194966 [details] revised patch Revised patch that uses openssl to generate the random base64 string (thank to matthew@ for the suggestion).
A commit references this bug: Author: leres Date: Thu Aug 16 01:26:37 UTC 2018 New revision: 477305 URL: https://svnweb.freebsd.org/changeset/ports/477305 Log: Apparently starting with version 20080615.2 dhcp6c refuses to run without a dhcp6cctlkey file. Use openssl to generate one from the rc.d script when it is missing. PR: 229400 Reviewed by: ler (mentor) Approved by: maintainer timeout (6 weeks), ler (mentor) Differential Revision: https://reviews.freebsd.org/D16739 Changes: head/net/dhcp6/Makefile head/net/dhcp6/files/dhcp6c.in