Routing

See ...this is my network.. Firewall
|
External ISP network-Internet Router ---Internet switch --Internal(LAN)
switch---proxy (both internal external nic is connected to lan
switch)..(internet switch also connected to firewall)

This is my lan configuration..
Internal card:( Figure 1)

Ip address: 132.149.2.75
subnet mask: 255.255.0.0
Gateway: 132.149.2.254

External card(Figure 2)

Ip address : 192.168.10.50
subnet mask : 255.255.255.0
Gateway : 192.168.10.101(firewall)

First I try this in my linux machine...I configured 192 series ip(As is
Figure 2)..I assigned DNS ip in etc/resolv.conf...
On that time i can able to access the internet through mozilla.

After that I removed the configuration...

Now I insert another network card...Now I had 2 cards..
I configured both cards(One is internal(as in Figure 1) another is
external(as in Figure 2).

Now I can able to ping my DNS ip 61.1.96.69..nslookup "www.yahoo.com"
working...all is working...

My squid is properly configured ..

Now from my client machine(any 132.149. series) I can t access the
internet...

It gives "Connection timed Out"

I think both nic is not communicating...I have enabled the IP
forwarding also...

What should i do?

Any Routing entry should be added?
Any firewall settings?