Comment # 3 on bug 1202792 from Reinhard Max

OK, I think now I get it. OpenVPN can be compile-time configured to either use
netlink (default) or iproute2, but only the latter allows entirely unprivilegd
setups.

But does switching back from netlink to iproute2 have any negative effects on
performance or functionality for setups that start openvpn as root?

I wonder how widely used entirely unprivileged setups are, given that it took
almost a year until we got a complaint that we don't support them anymore.