Information
The ip6srcrouteforward parameter determines whether or not the system forwards IPV6 source-routed packets.
The ip6srcrouteforward parameter will be set to 0, to prevent source-routed packets being forwarded by the system. This would prevent a hacker from using source-routed packets to bridge an external facing server to an internal LAN, possibly even through a firewall.
Solution
In /etc/tunables/nextboot, add the ip6srcrouteforward entry-
no -p -o ip6srcrouteforward=0
This makes the change permanent by adding the entry into /etc/tunables/nextboot.