If you happen to detect a bruteforce attack on your self-hosted WP instance, this would be the IPTables syntax to block it:
iptables -A INPUT -s 119.81.130.34 -j DROP
Whenever you miss the attacker, and you’re ready to unblock, you may just type:
iptables -D INPUT -s 119.81.130.34 -j DROP
Hope this helps!