It looks like ifupdown tries to configure the VLAN a second time when it comes across the inet6 definition in /etc/network/interfaces.
This fails as the VLAN interface was already setup in the inet definition of the same interface. It looks like a conceptual error in the interfaces(5) syntax.
It looks like ifupdown tries to configure the VLAN a second time when it comes across the inet6 definition in /etc/network/ interfaces.
This fails as the VLAN interface was already setup in the inet definition of the same interface. It looks like a conceptual error in the interfaces(5) syntax.