Potentially complicated Port Foward problem...

F

Feileung

Limp Gawd
Joined
Oct 15, 2005
Messages
251
My network is set up as so:

Cable modem in my neighbors apartment

His WiFi router (not sure of model) connected directly to that modem

Cat-6 cable running from Ethernet port of his WiFi router to my apartment

Same Cat-6 cable connected to my Linksys WRT54GL v. 1.1 running DD-WRT v24-sp2 (10/10/09) min

My apartment is served wirelessly by this WRT54GL

My problem is that I can't get port forwarding to work. I've tried w/Tomato Firmware and now DD-WRT with no luck. I have set up port forwarding multiple times in the past w/no problem (different routers, not this one but it's nothing special set up wise). My computers are running Win7 and OSX 10.4.

I've run port tests from various sites and they always say that the port is blocked (connection timed out or refused, message seems to vary). I've tried changing the port numbers, even tested with just port 21 for FTP, and no luck.

My assumption was that being plugged into his WiFi router w/Cat-6 was similar to being connected to a hub but now I'm wondering if it is in fact doing some routing and affecting my port forwarding.

Do I need to do some sort of chained port forward? ie. forward from his router to mine and then to my computers?

Anyone have any ideas? Oh, I should mention that the cable modem only has 1 ethernet port on it so plugging into that is not an option.

Thanks!
 
You're double-NATed. His router is using NAT to connect the Internet to his LAN, then you're doing NAT again to connect your LAN to his LAN. The connections aren't passing from his WAN to LAN, so they're never even getting to your WAN to be forwarded to your LAN. In order for port forwarding to work on your router, all of those forwards would also need to be set up on his router, forwarding to whatever IP your router is getting on its WAN interface. This also means those ports cannot be forwarded to his PCs.

A more expensive but simpler option is to pay the ISP for an extra IP address (usually $5/mo) and plug a simple hub or switch into the cable modem, then plug both routers into that. Each router will get its own public IP address from the ISP, so each router's WAN interface will be directly "on the Internet" and port fowarding will work properly on each router. Essentially you'll both have your own separate Internet connections, just physically going through one modem.
 
Thanks for confirming my suspicions InvisiBill. I'll get access to his router and set it up appropriately.

Keiichi, internet or not we'd have a LAN set up for our own purposes (neighbor is an old friend). This situation is pretty much the same as if we were roommates. Another cable modem on the network would just complicate things.
 
Feileung said:
Keiichi, internet or not we'd have a LAN set up for our own purposes (neighbor is an old friend). This situation is pretty much the same as if we were roommates. Another cable modem on the network would just complicate things.
Click to expand...

Actually no, you and your neighbor do not have a LAN. You have a LAN and your neighbor's connection is a WAN to your LAN. You guys live in a separate dwelling which violates the TOS. Rationalize it all you want, it's still breaks TOS and therefore against forum policy to even post a question like that.
 
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