[ 488.551062] Could not find device with ifindex 2000 in netnsfd 11 [ 488.551201] Could not find netns with fd: 2000 [ 488.551273] Cannot link a netdevsim to itself [ 488.551358] Format for linking two devices is "netnsfd_a:ifidx_a netnsfd_b:ifidx_b" (int uint int uint).