so - is your cable modem a router too? or just a modem?
is that airport express the only router on your network?
if so, i am not sure that you can use it like that. your cable provider is probably giving you one public IP address. that is normally taken by the gateway (or primary rotuer) on your network.
because the express only has the one ethernet port, that port is either for incoming traffic and then it distributes private IP addresses on the wireless network. i don't think that that one port can do both: act as the WAN and the LAN connection.
i believe you need some sort of router plugged in in between your modem and your switch.
That should take care of it.
To answer your question: The cable modem is just a modem, not a router.
I'm sorry I'm not quite following what you're saying about the gateway or primary router taking the public IP, and how that wouldn't work.
In the past, I have used the switch in this way to allow another computer which didn't have a wireless card to connect to the internet via ethernet.
I had the cable modem connected to the switch, then the switch connected to the Airport Express. I would plug the other computer into the switch and it would get to the internet just fine. Other computers could use the wifi connection as well, and it worked.
I expected the SB to behave the same way the ethernet-connected computer did in the past.
Does that help?
Have you had any luck with this setup?
I'm trying to get exactly the same thing operating.
I have Virgin Media fibre-optic cable router, an Airport Express, my new Slingbox Solo and a Belkin wired 10/100 switch I just purchased to try to join things up.
I have ethernet-connected the Virgin Media cable router to the Belkin switch input and added the Airport Express and Solo.
I can see the internet from my laptop successfully via either the Airport Express or via a direct cable into the switch.
I cannot see the Solo from my laptop whether connected to the internet wired (via the switch) or wirelessly via the Airport Express.
Nope - I haven't had any luck yet. I've been hoping I could get help here on the boards but not yet. You're right, if your laptop can get to the Internet via the switch, the Solo should, I would think. But, maybe we're wrong.
For what it's worth, I went to Best Buy who sells the Slingbox and Apple, and they said this configuration should work. But, Best Buy isn't known for being super tech-savvy in the store either.
I'm baffled. It would be ridiculous I'd think, to need to buy another Airport Express as stated in the setup instructions above. A switch should do the same thing as the Airport Extreme with multiple Ethernet ports. I'd LOVE to get some help from Slingbox, as would you, I imagine. Maybe now that two of us are struggling with this, someone will help.