Verifique o conteúdo do arquivo /run/network/ifstate
. ifup
e ifdown
usam esse arquivo para observar quais interfaces de rede podem ser ativadas e desativadas. Assim, ifup
pode ser facilmente confundido quando outras ferramentas de rede são usadas para abrir uma interface (por exemplo, ifconfig
).
De man ifup
The program keeps records of whether network interfaces are up or down. Under exceptional circumstances these records can become inconsistent with the real states of the interfaces. For example, an interface that was brought up using ifup and later deconfigured using
ifconfig
will still be recorded as up. To fix this you can use the--force
option to forceifup
orifdown
to run configuration or deconfiguration commands despite what it considers the current state of the interface to be.