Hello,
one of my hosts has one wired and one wireless interface, and both
interfaces have /64 IPv6 addresses in different subnets. I've noticed
that this host doesn't use the IPv6 address of the outgoing interface
(i.e., the wireless interface) as its source address, but, instead, the
IPv6 address of the wired interface. I've seen this even when the wired
interface is down. According to the routing table, I don't understand
why the IPv6 address of the wired interface should be used in this case.
I've already tried to increase the priority of the wireless interface
(to priority 0), but this doesn't help.
Example:
wired interface: 2001:db8:10:10::2/64
wireless interface: 2001:db8:100:100::2/64
destination address: 2001:db8:10:20::1/64
The default route is set to the router address 2001:db8:100:100::1, so
the wireless interface is the outgoing interface. The router with the
address 2001:db8:100:100::1 can directly reach 2001:db8:10:20::1 by
using its interface with address 2001:db8:10:20::2/64.
What surprises me is that although the correct outgoing (wireless)
interface is used, an IPv6 packet to 2001:db8:10:20::1 has the source
address of the wired interface 2001:db8:10:10::2.
Regards
Andreas
