Iptables don't understand network address

I have a local network with 10.0.2.0 address and 255.255.254.0 netmask.

My firewall have IP 10.0.2.130 on eth0.
My station have IP 10.0.2.2.

I configure my firewall for drop the ping from the station with 1 rules :

# iptables -A INPUT -i eth0 -s 10.0.2.2 -p icmp -j DROP

When I ping the firewall from my station (ping 10.0.2.130) , I receive an response from the serveur

Why ?

What is the problem ? My netmask ?

If i modify my netmask to 255.0.0.0 on firewall and my station, the ping doesn't work. Normal !

Iptables don't understand network address not in class A, B or C

HELP ME !!!