Re: IPv6 default routes / NM vs. kernel autoconfig

[Tore Anderson <tore anderson redpill-linpro com>]

* Stuart D Gathman

> While it doesn't actually break, I have a related issue with DHCP6. When
> RA enables DHCP6 (and NM set to "Automatic"), I end up with *both* the
> RA and DHCP addresses.   And it keeps accumulating more IPs over time! 
> Here is what I have after 6 days uptime (prefix changed), the ::34 is
> the DHCP6 assigned IP.
> 
> em1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
>         inet 192.168.9.34  netmask 255.255.255.0  broadcast 192.168.9.255
>         inet6 2001:db8:dead:beef:d070:56c1:718b:984a  prefixlen 64
> scopeid 0x0<global>
>         inet6 2001:db8:dead:beef:c14a:1e6f:cb6c:3789  prefixlen 64
> scopeid 0x0<global>
>         inet6 2001:db8:dead:beef:781b:86da:f62a:3c46  prefixlen 64
> scopeid 0x0<global>
>         inet6 2001:db8:dead:beef:20fd:9bd1:bec7:c06f  prefixlen 64
> scopeid 0x0<global>
>         inet6 2001:db8:dead:beef::34  prefixlen 64  scopeid 0x0<global>
>         inet6 2001:db8:dead:beef:20c:f1ff:fed9:97b4  prefixlen 64
> scopeid 0x0<global>
>         inet6 fe80::20c:f1ff:fed9:97b4  prefixlen 64  scopeid 0x20<link>
>         inet6 2001:db8:dead:beef:5820:434c:936c:f4c1  prefixlen 64
> scopeid 0x0<global>
>         inet6 2001:db8:dead:beef:cd72:db54:d19b:49d7  prefixlen 64
> scopeid 0x0<global>
>         ether 00:0c:f1:d9:97:b4  txqueuelen 1000  (Ethernet)
>         RX packets 1412101  bytes 1128925860 (1.0 GiB)
>         RX errors 0  dropped 0  overruns 0  frame 0
>         TX packets 737197  bytes 72349628 (68.9 MiB)
>         TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
> 
> It looks like an attempt to use the privacy protocol to assign random
> IPs that change periodically, but it forgets to remove old IPs.

Actually, this looks completely normal (except for the "prefixlen 64"
for the DHCPv6-assigned address, something which was recently fixed in
NM). The 2001:db8:dead:beef:20c:f1ff:fed9:97b4 one is the permanent
EUI-64-derived address obtained through SLAAC, and the others are
privacy addresses. Your OS will probably generate a new one every 24
hours. However, the old ones will remain valid for quite some time
before they are removed, so it is normal to see them accumulate up until
a certain point. You should look for a tool which tells you the
remaining valid lifetime for each individual address. On Linux, this
would be "ip -6 address list", but I guess you're running something else.

Best regards,
-- 
Tore Anderson
Redpill Linpro AS - http://www.redpill-linpro.com