Port Forwarding on 2 Routers (Weird Problem!)

[insideout]

Hi, my first post here, and this query that I'm posting isn't simple. The support staff at my DSL provider's help center didn't know what to do about it.

A little history ... :

So I have this 2MB DSL line, and I'm an avid downloader, to say the least! I use torrents a lot, and my torrent client of choice is μTorrent, and for my downloads to go at full speed, it goes without saying that I need my port to be forwarded properly. That was never a problem, because I always used the modem directly connected to my computer. But a couple of months ago, I bought a wireless router (Linksys WRT54G) for my home, and ever since, things have been ... confused.

The easiest solution to forward ports on the two router setup was to not use the internet port on the wireless router, and plug my modem into one of the 4 switch ports on it instead. That way, the router is, for lack of better words, by-passed, and the port forwarding works fine. But using this setup, there is another problem that comes up. Whenever I try to connect a wireless device (laptop), I need to manually configure the IPs on the laptop. If I let the DHCP assign IPs, the network connects, but the internet doesn't work.

So the next solution I had was visit www.portforward.com (great resource, btw), and follow their instructions on forwarding ports on a 2-router setup. Although pretty confusing, for me at least, I finally managed to get that setup to work, and my ports were opened successfully through both routers, using DHCP to assign the IPs. Of course, the IP on my computer (the one I use for downloading) had to be static for the port forwarding to work, so I assigned an IP from the wireless routers DHCP range to it (192.168.0.110).

Now, the problem ... :

Everything here works fine then, except one problem ... Somehow, my wireless router seems to keep "releasing" it's IP. I can't figure out why! I'm using the following IPs on my network:

ADSL modem

IP: 192.168.1.1

DHCP info

Starting address: 192.168.1.1

End IP address: 192.168.1.254

Lease Time: 1 day

Wireless Router

IP: 192.168.0.1

DHCP info

Starting address: 192.168.0.100

Max DHCP users: 50

Lease Time: 1 day

My Desktop Computer

(Connected to the wireless router with a wire - not wireless)

IP: 192.168.0.110 [i use this IP (manually configured, for Port Forwarding) so that it stays within the DHCP range, and doesn't conflict with other devices that try to connect through wireless]

Subnet Mask: 255.255.255.0

Default Gateway: 192.168.0.1

Lease Time: 1 day

What happens is, after some time, when I try to access the control panels of either devices from by browser (Firefox 3.0-RC1), neither of the IPs work. Rebooting the Linksys router fixes the problem, but after a while, it starts doing the same thing again. And while the control panel can't be accessed, my Port Forwarding also seems to get clogged up. When I reboot the wireless router, the Port Forwarding starts working again as well.

I've noticed a trend in all of this, a sort of "method to the madness". What happens is, when I turn on the setup for the first time, everything works smoothly. But when I run μTorrent once, and the little green circle tells me that everything's working fine, that's when the problems start! When I try to access the control panels after that, they don't respond. And, if I restart μTorrent after that, the Port Forwarding stops working as well, so were' back to square one. Another important thing to note here is that while my router control stops responding, other wireless devices also fail to connect to it, and the internet does not work on those other devices. However, it continues to work on my computer, whether I reboot the router or not.

Hopefully, now you see the whole circle that my problem runs in. I hope this is enough (if not too much) data for a diagnosis of this odd problem. I'm also attaching a few screen shots to help you understand the situation.

Home Network Schema

IP settings on the computer

Wireless Router - DHCP Server settings

Modem - DHCP Server Settings

Current Status of the Router

Port Forwarding on the Modem

Port Forwarding on the Router

Please, I need help with this. Any help sort this out would be greatly appreciated. Thank you.

[homecomputeraid]

Hello insideout,

Welcome to the forum!

Very nice and informative post. What you're doing when you "bypass" the router though isn't port forwarding, it's Local Area Network (LAN) switching. The router's four internal ports are switched ports, not routed ports. You're trying to make the WRT54G Wireless Access Point/Router act like a switch when it is a router.

Your ADSL modem is using a non-routable private IP Address Scheme. Both 192.168.1.0 with a 255.255.255.0 mask and 192.168.1.0 with a 255.255.255.0 mask are private IP schemes. http://en.wikipedia.org/wiki/Private_network

Do you have some form of authentication to get to the Internet? Some kind of login and password before you can actually connect and use a web browser? I suspect you may have to configure PPoE on your router.

To do so though, you'll have to use the router as a router, not as a switch. That means you'll have to cable the WAN port on the WRT54G to the Ethernet port on the ADSL modem. The authentication could make port forwarding more tricky to configure. You should really try downloading without it before even trying to configure it. Port forwarding allows Internet users to get to your PC, but should not affect your ability to download.

[insideout]

Hello insideout,

Welcome to the forum!

Very nice and informative post. What you're doing when you "bypass" the router though isn't port forwarding, it's Local Area Network (LAN) switching. The router's four internal ports are switched ports, not routed ports. You're trying to make the WRT54G Wireless Access Point/Router act like a switch when it is a router.

Your ADSL modem is using a non-routable private IP Address Scheme. Both 192.168.1.0 with a 255.255.255.0 mask and 192.168.1.0 with a 255.255.255.0 mask are private IP schemes. http://en.wikipedia.org/wiki/Private_network

Do you have some form of authentication to get to the Internet? Some kind of login and password before you can actually connect and use a web browser? I suspect you may have to configure PPoE on your router.

To do so though, you'll have to use the router as a router, not as a switch. That means you'll have to cable the WAN port on the WRT54G to the Ethernet port on the ADSL modem. The authentication could make port forwarding more tricky to configure. You should really try downloading without it before even trying to configure it. Port forwarding allows Internet users to get to your PC, but should not affect your ability to download.

Thank you for your reply. I think I forgot to mention this little detail in my extremely long post there. In the second solution i.e. the setup I'm using right now, I have plugged the cable from the Modem's Ethernet port into the Router's WAN port, which means that I'm using the router as a router. And in this setup, I have got the Port Forwarding to work properly. And Port Forwarding is important because most of the times, the torrents don't get up to full speed without it. I use PPPoE to connect to my DSL, and not Bridge, which means i don't have to connect each time. I just turn on the modem, and its connected.

Problem Clarification:

Everything is working fine. Wireless devices can access the internet, and Port Forwarding on my computer works. But the problem is ... when i run uTorrent once, that's when things get messy. After that, i can't access my Router or Modem control panels, and it seems like the browser can't find those IPs. After i exit uTorrent, the problem persists until i reboot my router. So I'm guessing this has something to do with the Port Forwarding messing with the DHCP or something, but I'm not sure. My knowledge ends here. Or it could have something to do with the manual assignment of IP to my computer, because even though it is in the DHCP range, the router cannot "sense" manually configured IPs as part of the DHCP. Or, could it have something to do with the IP i reserved for the router in the Modem's DHCP server?

Am i just confusing myself and everybody else?!

[homecomputeraid]

I'm sorry but not clear on whether you're doing PPPoE authentication to your ISP using the Router, or using your PC. The most reliable way, assuming everything works as it should, would be to have your router authenticate to your ISP. It can be confgured to do so, but it's a manual process on your part the first time you set it up.

ISP -->DSL Modem-->WRT54G-->PC's

PPPoE----------------->WRT54G

You should not have to reserve an IP on your LAN (your WRT54G's switch ports) for your DSL Modem because it's actually already configured with its own IP and it is giving a DHCP address to the WAN port of the WRT54G.

The addresses are given out like the arrows above. The WRT54G, if it does PPPoE, will have two IP addresses for the WAN adapter. One provided by the DSL Modem, and the other provided to a PPPoE adapter when the WRT54G connects to your ISP.

The router does not have to know the IP's you're assigning to the PC's to communicate with them. As long as they're in the right subnet everything will work. If the network between your DSL Modem and the WAN Port on the WRT54G is 192.168.0.0 255.255.255.0, make sure the network inside the WRT54G is different, something like 192.168.1.0 255.255.255.0.