[ 466.998511] Could not find device with ifindex 2000 in netnsfd 11 [ 466.998700] Could not find netns with fd: 2000 [ 466.998805] Cannot link a netdevsim to itself [ 466.998938] Format for linking two devices is "netnsfd_a:ifidx_a netnsfd_b:ifidx_b" (int uint int uint).