iptables in a hurry

Accepting incoming connections to a port only from specific hosts in the middle of the night:

iptables -I INPUT -p tcp --dport $dport -j REJECT
for ip in $ips; do
    iptables -I INPUT -p tcp --dport $dport --source $ip -j ACCEPT

We have to do it in the above order, since -I inserts the rule at the head of the list of rules.