I'm about to publish a fixed IPv6 address and I understand I can use the ip token command to lock the host part of the RA-assigned address to a fixed value. But I can't see an obvious place to configure this. The logical place would be in the ifcfg-<interface> file. Is there someplace else I should set this? NetworkManager? It looks like the new systemd-networkd has support for this but my interfaces seem to be configured from the old initscripts and the new systemd-networkd isn't installed. <https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/6/html/deployment_guide/s2-configuring_ipv6_tokenized_interface_identifiers>