K 10 svn:author V 6 tuexen K 8 svn:date V 27 2020-09-10T12:52:50.845067Z K 7 svn:log V 504 MFC r359487: Allow the TCP backhole detection to be disabled at all, enabled only for IPv4, enabled only for IPv6, and enabled for IPv4 and IPv6. The current blackhole detection might classify a temporary outage as an MTU issue and reduces permanently the MSS. Since the consequences of such a reduction due to a misclassification are much more drastically for IPv4 than for IPv6, allow the administrator to enable it for IPv6 only. Manually resolve conflict for BBR, which does not exist in stable/12 END