Proxy Server / can not access to Web

I installed 2 NIC in server,
external NIC (connect to outside network):
IP: xxx.xxx.xxx.xxx (real IP)
Mask: 255.255.255.224
Gateway: xxx.xxx.xxx.xxx (real IP,Cisco Router)
DNS1 & 2: xxx.xxx.xxx.xxx (ISP’s DNS)
internal NIC:
IP:192.168.0.11
Mask: 255.255.255.0
Gateway: no gateway
DNS1 & 2: ISP’s DNS
LAT:
0.0.0.1 to 0.0.0.1
10.0.0.0 to 10.255.255.255
172.16.0.0 to 172.31.255.255
192.168.0.0 to 192.168.255.255
Proxy Client1:
IP: 192.168.0.12
Mask: 255.255.255.0
Gateway: 192.168.0.11 (Proxy Server’s IP)
DNS: no DNS
I can not access to Web, what else I need to do? (I can Ping both server’s NIC,and get mail from mail server that installed in server)
Thanks very much.