29.12.2015 18:22, Sowmini Varadhan пишет:

Do you have admin control over the ubuntu router?
If yes, you might want to check the shared_media [#] setting 
on that router for the interfaces with overlapping subnets.
(it is on by default, I would try turning it off).

That didn't help, problem re-appears.
Thanks anyway, looks like I am going to disable accept_redirects then.
It seems buggy and obviously no one cares.