Modem only works coming into the output ports of router

[zephyrcat]

I'm really confused. I came back from travel and learned that our house's internet connection had been having trouble.

We have two internet connections - a DSL line and a cable line. Neither the DSL nor the cable works when plugged directly into a computer. The cable doesn't work when plugged into any of the router's ports either (although all the status lights are fine). The DSL doesn't work when plugged into the router's input port (the single port where it would normally be plugged in), but when plugged into one of the four output ports (where computers would normally be plugged in), it does work.

In short, I have tried every combination of our DSL router, cable router, comptuer, and Linksys WRT54G, but the only one that works is the DSL plugged into one of the output ports of our router (WRT54G).

I don't know a ton about networking, but I do know enough to keep our wireless network and NAS up.

Why on earth does this setup work and why doesn't the correct setup work? (I have called the cable company already. They claim the problem is not on their end. I'm assuming the DSL company will say the same thing.)

Thanks!

 

[thiggins]

1) How are the two Internet connections normally connected?

2) What OS are the computers using?

3) If you are using Windows and repair the network connection, what IP address do you get?

 

[zephyrcat]

Normally only one connection is used. I solved the problem by waiting a while and then replacing the router.