[ 485.216655] Could not find device with ifindex 2000 in netnsfd 11 [ 485.216829] Could not find netns with fd: 2000 [ 485.216928] Cannot link a netdevsim to itself [ 485.217052] Format for linking two devices is "netnsfd_a:ifidx_a netnsfd_b:ifidx_b" (int uint int uint).