flowlabel_reflect

file: /proc/sys/net/ipv6/flowlabel_reflect
variable: net.ipv6.flowlabel_reflect
Official reference

Automatically reflect the flow label. Needed for Path MTU Discovery to work with Equal Cost Multipath Routing in anycast environments. See RFC 7690 and: https://tools.ietf.org/html/draft-wang-6man-flow-label-reflection-01 TRUE: enabled FALSE: disabled Default: FALSE

source