Hi,
i have 40 client's in my network, that connected to internet via
squid server (WebProxy). i want none of these client can't ping my squid server bat squid server can ping them.i wrote these rules but it is'nt work.

iptables -P INPUT DROP
iptables -P OUTPUT DROP
iptables -A INPUT -p icmp -s 192.168.23.1/24 -d 0/0 -j ACCEPT
iptables -A OUTPUT -p icmp -s 192.168.23.1/24 -d /0/0 -j ACCEPT

first of all you need to see all your iptable list

iptable -L

iptables -A INPUT -s 192.168.1.0/24 -p icmp -j ACCEPT