How do I block specific incoming ip address?

following iptable rule will drop incoming connection from host/IP 72.30.2.43:

iptables -A INPUT -s 72.30.2.43 -j DROP
iptables -A OUTPUT -d 72.30.2.43 -j DROP

service iptables status

iptables -D INPUT -s 72.30.2.43 -j DROP
iptables -D OUTPUT -d 72.30.2.43 -j DROP