Linux – How to check/enable promiscuous mode

Many if not all network traffic capture utilities require that the network adapter has the promiscuous mode enabled.

To check if the promiscuous mode is on run:

netstat -i
Kernel Interface table
Iface MTU  RX-OK RX-ERR RX-DRP RX-OVR TX-OK TX-ERR TX-DRP TX-OVR Flg
eth0  9001 9095  0      0      0      10367 0       0     0      BMRU

Look at the Flg column – if the P flag is missing the mode is not enabled.

To enable it run:

ifconfig eth0 promisc

or

ip link set eth0 promisc on