In cases where we cannot use other tools, they are not available or we cannot install them, we can use this bash one-liner to detect active hosts:

for i in {1..254}; do ping -c 1 -W 1 192.168.250.$i 2>&1 > /dev/null && echo "[+] 192.168.250.$i $(host `192.168.250`.$i | awk 'NF{print $NF}')" | sed 's/\.$//'; done

Be careful because only 192.168.250/24 is scanned. You must adapt it to your particular case.