vcsa iptables

I am new to iptables.

I want to open all ports of vcsa (everything ) for few servers. And close any traffic from any other server (only for incoming traffic )

is there any problem with these rules.

iptables -A INPUT -s 192.168.1.12/24 -p all -j ACCEPT  # this will open everything from .12

iptables -A INPUT -s 192.168.1.13/24 -p all -j ACCEPT

<few more servers......>

iptables -A INPUT -j DROP # drop everything

any suggestion.