Get a request through a router to a specific LAN IP?

To anyone with knowledge about LANs, NATs, and port forwarding around a router.

I am on an iMac OS 9.1 on a small home LAN (3 macs) connected by a simple hub to a Cisco 675 router which is connected to ADSL (640 Kb/s Qwest)

I see from other postings that it is not always trivial to play host for an online game if you have DSL and are on a LAN. Apparently requests from other players to join your game must be directed by the game server through a specific game port in the router to your location in the LAN by a little thingy called NAT (though why I don't need NATs help to direct my web traffic to my little box I have no idea). I have been wrestling with this problem off and on for about 2 months now and am getting nowhere. I hope someone in the forum can help me out.

A post in Help from Gameranger (the Mac gameserver in this case though I don't think this problem is unique to Macintosh in anyway) said, after trying to explain about port forwarding and NAT, to enter the local address of the router "into your browser"! The local address for the router is 10.0.0.1 but I have no idea where to enter such an address into a browser (They don't answer e-mail requests for clarification). I tried the proxy box in IE and all it did was lock up my computer. Anyone have any suggestions on this fix??

I tried to learn a little about my router, NAT, and port forwarding. If I have it right, NAT permits the router to determine which box on a LAN incoming requests should be routed to. My computer has the local LAN address of 10.0.0.4. the router's local address is 10.0.0.1.

The following excerpt from a tech post about the Cisco 765 .
SWCP Knowledge Base
How does one set up port forwarding on the Cisco 675 router?
Article ID: 94
Updated: Aug-07-2002
The command to set up port forwarding on the Cisco 675 is:
set nat entry add <internal ip of server> <port number> <protocol>
For example to set up a mail server whose LAN address is 192.168.0.2:
set nat entry add 192.168.0.2 25 tcp

They seemed to be trying to do the same thing for the mail server that I want with my imac. I entered two commands to the router
"set nat entry add 10.0.0.4 23978 tcp" and an identical one for udp.
they both seemed to take. But I still couldn't host. (23978 is the port given for that game)

Entering the local address of the router (10.0.0.1) in the command line also didn't seem to work.

If anyone knows about this stuff or knows what I am doing wrong I would really appreciate a response.

Pepper

 

Go into the router settings and type "sh NAT" and post back the results. If you are going to use NAT your PC needs a fixed IP address nad you need to know your routers external WAN address....if that's not a static IP I wouldn't even bother trying this. Also post back the WAN address and your local address.

 

Thanks for the reply Rockn...
Here are the results:

cbos>sh nat

NAT is currently enabled

Port Network Global
eth0 Inside
wan0-0 Outside 67.40.163.12
vip0 Outside
vip1 Outside
vip2 Outside

Local IP : Port Global IP : Port Timer Flags Proto Interface
10.0.0.4:23978 *****:23978 0 0x00041 tcp eth0
10.0.0.4:23978 *****:23978 0 0x00041 udp eth0
10.0.0.4:50349 67.40.163.12:16949 39150 0x00146 tcp eth0 wan0-0
10.0.0.4:49152 67.40.163.12:17707 60 0x00046 udp eth0 wan0-0

cbos>
The outside (is that the same as the WAN address?) IP address is assigned by DHCP but only changes when the power goes off on the router so it is pretty stable. and is that shown (67.40.163.12) the local address for the Cisco 765 router is 10.0.0.1 and my local iMac is 10.0.0.4 and these are static. These are the only IP addresses I know. I thought the external router WAN IP was the same as the main outside IP for the whole LAN. If not where do I find that?

You can see the two entries that I set up at port 23978. I don't know what the others are I didn't set them.

I hope I can still do this with a dynamic IP.
Thanks again for the response. I feel like I am at least making some progress.
Pepper.

 

Set your local iMac's address to 10.0.0.4 if that's what you want to use. To add a NAT entry first delete the ones you just added by entering "set nat entry delete 10.0.0.4 23978 TCP" do the same for UDP and when that is done type in "write" and enter. Type "sh NAT" again. Those entries should be gone. Now add the proper entries like this: "set nat entry add 10.0.0.4 23978 67.40.163.12 23978 TCP" and enter. Do the same for UDP and then enter "write". Verify they are entered by "sh NAT" again. That should be all you need to do if those are the only ports you need for the game.

 

Thanks again Rockn,

Its me thats rockn' an a rolling now. It worked like a charm and what is better -- I think I understand the rationale. I can't believe that after messing with this thing for a couple of months, I got it to work in one day of being on here.

Hope I can return the favor someway.
You guys know what you are doin'!

Pepper