net.ipv4.tcp_syncookies = 2 net.ipv4.tcp_window_scaling = 0 net.ipv4.tcp_timestamps = 0 net.ipv4.tcp_sack = 0 Wait for IP 127.0.0.1 to become available . OK Wait for IP ::1 to become available . OK Testing clsact...ok Testing XDP...ok :: [ PASS ] :: Test '32..40 selftests: bpf:test_tcp_check_syncookie.sh [PASS]'