Forwarding packets on iptables firewall

[crux crux]

Hi people,

I have two machines which are connected to iptables firewall.
On firewall I have following rules

iptables -A FORWARD -i eth0 -o eth1 -j ACCEPT
iptables -A FORWARD -i eth1 -o eth0 -j ACCEPT


echo 1 > /proc/sys/net/ipv4/ip_forward  ( on firewall )

ip address of machineA is 192.168.1.2
ip address of machineB is 10.1.1.2
default gateway for machineA is 192.168.1.1 ( eth0 )
default gateway for machineB is 10.1.1.1  ( eth1 )


machineA -------- eth0(firewall)eth1-----
-machineB
I want make possible traffic flow from machineA to machineB.

The above rules should do that, but because of something I cannot ping
machineB from machineA.

OS is debian. Any help is welcome.

Regards

Crux