I will use my current set-up as an example. I use a local ISP FasTucson.com, formerly AZStarNet.com. I have a Cisco 678 DSL modem, which is connected to my Netgear RT314 Internet Router, which is connected to two computers. The Cisco is configured as DHCP client (I have a dynamic public IP address). My Netgear Router and my two computers have fixed private IP addresses.
First step is to determine which ports and protocols are in use by a particular game. I will use Age of Empires for my example. Consulting Microsoft's DirectX FAQ or my list of game ports, we find that Age of Empires uses DirectPlay 7, which TCP port 47624 is used initally and ports in the range of 2300 to 2400 using both TCP and UDP protocols are used subsequently.
Because I actually have two NAT devices (both the modem and router perform NAT). I actually have to forward the ports properly on both devices.
I must forward all the ports on the Cisco 678 modem (10.0.0.1) to my Netgear Router (10.0.0.2). My Netgear router's "public" (as seen by the Cisco modem) IP address is the default 10.0.0.2. If you don't have a router then use the private IP address of your computer.
Telnet to the modem. To access Telnet from a Windows PC:
User Access Verification
Password:********
cbos>enable
Password: ********
cbos#show nat
NAT is currently enabled
Port Network Global
eth0 Inside
wan0-0 Outside xxx.xxx.xxx.xxx
vip0 Outside
vip1 Outside
vip2 Outside
cbos#set nat entry add 10.0.0.2 47624 tcp
cbos#set nat entry add 10.0.0.2 2300-2400 0.0.0.0 2300-2400 udp
cbos#set nat entry add 10.0.0.2 2300-2400 0.0.0.0 2300-2400 tcp
cbos#show nat
NAT is currently enabled
Port Network Global
eth0 Inside
wan0-0 Outside xxx.xxx.xxx.xxx
vip0 Outside
vip1 Outside
vip2 Outside
Local IP : Port Global IP : Port Timer Flags Proto Interface
10.0.0.2:47624 *****:47624 0 0x00041 tcp eth0
10.0.0.2:2300 *****:2300 0 0x10041 udp eth0
-2400 -2400
10.0.0.2:2300 *****:2300 0 0x10041 tcp eth0
-2400 -2400
cbos#write
Warning: traffic may pause while NVRAM is being modified
NVRAM written.
cbos#exit
To use port ranges you must have version 2.4 or greater. See Update instructions. I actually installed it usings Qwest's DSLUpdater, as Cisco requires you to register to get the fix.
If you cannot or will not download the updated firmware you can route all ports to your machine. However, be aware that this reduces your security as well.
cbos#set nat entry add 10.0.0.2
To remove the routing you can use the following command:
cbos#set nat entry delete 10.0.0.2
I must also forward the proper ports on the Netgear RT314 router The ZyXEL Prestige P310/P314 is internally identical to the Netgear RT311/RT314. to my computer. You must have a fixed private address; if you have a dynamic address your computer may be assigned a new IP address and you will no longer be able to play online games. My computer's fixed private IP address is 192.168.0.2.
| Start Port | End Port | Server IP Address |
|---|---|---|
| 47624 | 47624 | 192.168.0.2 |
| 2300 | 2400 | 192.168.0.2 |
| These ports are for Microsoft's DirectX 7 compatiable games. For different games or additional ports see my TCP/IP ports list. | ||
