[FS#656] IPv6 relay mode does not work

[LEDE Bugs]

The following task has a new comment added:

FS#656 - IPv6 relay mode does not work
User who did this - Alex Tomkins (tomkins)

----------
Sorry for replying to a closed bug - but I believe this is the exact problem I've had. My ISP provides a /56 and a DSL router, but sadly that router doesn't support prefix delegation, which means DHCPv6 and RAs being served from a /64.

OpenWrt 15.05 was absolutely fine, however upgrading to LEDE 17.01.4 relay mode was unreliable. RAs were being received, my Linux server receiving these seemed just fine, my MacOS laptop received the address - but mtr showed the lack of a default gateway.

One thing which fixed it for me - removing ula_prefix entirely.
----------

More information can be found at the following URL:
https://bugs.lede-project.org/index.php?do=details&task_id=656#comment4339