Comment 16 for bug 997605

I'm having a similar issue. I have disabled Route Advertisement (accept_ra=0) in sysctl.conf file, but at boot I still get a default IPv6 route to my router with an RA flag, which means it was assigned using a ra.

The default route expires soon after the boot, as it does not get renewed. This shows that the accept_ra=0 is actually working. It's not accepting route advertisements anymore, so this route does not get renewed. However, why do I still get the first route over RA? It's bugging my interface, as it has a gateway rule, but is not able to set it as there is already a default route assigned by a RA. I have no idea why it's even possible to get a route automatically before the actual interface is up (it's trying to assign the gateway I put in the interfaces file, but I get an error: File exists.).

Only solution so far is removing the gateway line, causing the default route to appear automatically by RA and setting accept_ra to 1.