Wireless router headaches (awesome photoshop work inside!! must L@@K)

[teddyFBI]

Why does my wireless router work when connected directly to my cable modem...but not when the input signal is coming via a big ethernet SWITCH.

I've posted about this before and couldn't get to the bottom of it, and I wanted to try tackling it again...but met failure [img]/images/graemlins/frown.gif[/img] ugh ugh ugh

Picture a standard cable modem. Well, when the outgoing wire goes from it directly into my wireless router, I'm able to configure my home wireless network just fine, and everything works.

HERE'S THE PROBLEM -- what I'm going for is a dual wired/wireless network...5 years ago, my parents had a big ethernet switch installed, and then threaded wires throughout my house...so i figured "oh, well since each one of those wires coming out of the switch carries an ethernet signal, I'll just take one and use it as the input to the wireless router and 'boom' wireless network enabled...after all, I reasoned, the wireless router doesn't know the difference between a signal coming directly from the cable modem, and one coming from the switch, right?

Well, apparently that's WRONG, b/c it works when the incoming ethernet signal comes straight from the cable modem, but NOT when it comes from one of the output ethernet wires from the switch. When I try the latter, the router successfully CREATES the wireless networ, and all my laptops can "see" it and appear to be exchanging data packets with it, but cannot connect to the internet

i'm somewhat tech savvy, and i've spent at least 8 hours of my life on this to no avail.
Help.

I made a pictorial display of this -- please don't allow my superior photoshop skills to have been employed in vain