Block IP address in firewalld
sudo firewall-cmd --add-rich-rule="rule family='ipv4' source address='89.20.160.77' reject" --timeout=1h
Valid values for timeout - numbers followed by s, m or h
firewalld/
Log denied connections in firewalld
Edit file /etc/sysconfig/firewalld:
FIREWALLD_ARGS=--debug=10