I have installed my modem/router as a default gateway with IP 192.168.0.1, and then attached a multi-port switch to it. My two computers are then attached to the switch.
How can I get to the switch via web browser (to configure it)? If I enter 192.168.0.1, I directly access the router and the switch is simply passed through.
I'm guessing you are using some sort of Windows environment.
In that case, win mtr might be of use, use it to connect to the router/modem, it should list all in between noded (including the switch).
Perhaps simpler solution would be to connect to the web gui of the modem/router, and check IP's of all devices connected to it. One of them should be the switch.
Note: Bear in mind, if you are talking about layer 2 switch, those do not have any IP address, since only layer 3 of networking stack has IP address.
I was in a similar situation when I outgrew my Airport Extreme gateway and added a Cisco E3000 as a router behind the Extreme. I think this may help with your issue.
What I did was I logged into the E3000 before connecting it to the gateway and re-numbered it as 192.168.1.2 which was within the addressable range of the 192.168.1.1 device. I also changed its default setting from gateway to router and turned off DHCP.
Then when I connected it to the gateway device 192.168.1.1 and it came up ready to go.
Hope that helps.
