[root@localhost ~]# vim ip.txt
192.168.177.1

192.168.177.2

192.168.177.3

192.168.177.4

192.168.177.5

192.168.177.6
172.168.177.8
127.0.0.1

[root@localhost ~]# vim if.sh

#!/bin/bash
ip=(`cat /root/ip.txt`)
for i in ${ip[*]}
do
        if [[ $i == "192"* ]]; then
                echo "$i is ok"
        else
                iptables -A INPUT -s $i -j DROP &> /dev/null
                echo "$i drop"
        fi
done

[root@localhost ~]# sh if.sh