+fwmark_reflect - BOOLEAN
+ Controls the fwmark of kernel-generated IPv6 reply packets that are not
+ associated with a socket for example, TCP RSTs or ICMPv6 echo replies).
+ If unset, these packets have a fwmark of zero. If set, they have the
+ fwmark of the packet they are replying to. Similarly affects the fwmark
+ used by internal routing lookups triggered by incoming packets, such as
+ the ones used for Path MTU Discovery.
+ Default: 0
+