IPS Modem to Vonage router to Time Capsule to Airport Express. Now I want to add a guest network.

Question

I want to set up a guest network.
I understand that there can only be one main router and the others should be in bridge mode to set the guest network feature on the Time Capsule.
If I set the Time Capsule from bridge mode to "DHCP + NAT" then I lose my internet.
Since I think the Vonage router is set as the main router how can I swap that function with the Time Capsule or perhaps that cannot be done.
Please let me know what I should try or whether to give up.
Thanks.

Answer 1

Thanks. I understand you want to "swap" your Vonage box with your Time Capsule. That will require re-enabling the Time Capsule's DHCP and NAT as you already attempted and explained in your original post, connecting the Time Capsule directly to your modem, and installing the Vonage box "downstream" of the Time Capsule by connecting it to a Time Capsule LAN port.
I assume you using your Mac wirelessly, that you have cable Internet (as opposed to DSL, FiOS, satellite, or office / school wired LAN), and that right now everything is working including your Vonage telephone service. If any of that is not correct, stop here and let me know.
You should also print these instructions, since you will be unable to communicate with either your Mac or your phone until you are finished and everything works correctly. If all else fails you may have to begin all over again with a "hard reset" of both your Time Capsule and the Vonage box and reconfigure them completely. Any Time Machine backups already completed will not be affected though.
Then:
Power down your cable modem: unplug it from the wall receptacle.
Disconnect the Ethernet cable linking the Vonage box and the Time Capsule. Set it aside for now.
Disconnect the Ethernet cable end attached to the Vonage box's blue port, and connect it the Time Capsule's WAN port instead.
Take the cable you set aside and connect the Vonage's blue port to one of the three Time Capsule's LAN ports.
Power up your modem and wait a moment or two for it to complete its startup sequence.
On your Mac, open AirPort Utility and reconfigure your Time Capsule's Router Mode to "DCHP and NAT" as you did previously. Update and allow a moment or two for it to reset.
Verify that you can use your Mac to load web pages and that your Time Machine backups continue to occur as usual.
Should something not go as expected and you need to make changes, be absolutely certain to power down your modem before changing what you connect to it.
Next:
The following Vonage video will illustrate the remaining steps particular to the Vonage box: Set Up Vonage Box With Router
Review their tutorial and make sure all its instructions make sense for what you have. If something doesn't, write back and I'll try to figure it out.
... how to make the vonage router a bridge.
Unless you want to use the Vonage box's LAN (yellow) port to connect an additional wired computer or other network it's not necessary to reconfigure it as a bridge. The Vonage's router will just remain unused.
If you want to do that though, you must log in to the Vonage box's configuration web page. Its address will be assigned by your Time Capsule, sequentially: for example if your Mac's IP address is 10.0.1.2 your Vonage box might be 10.0.1.3 or something along those lines. You may have to experiment to find out what it is (see Note below). Once you find it though, you will be presented with a login page resembling the following:
Its default User Name is router and so is its password. Click Go to log in.
Once there, navigate to Basic Setup > Local Network Setup, and change DCHP Server to No as in the following:
Click Apply and you're done.
Note: just like all non-portable network devices, it makes sense to assign the Vonage box a static IP address: Basic Setup > Connect to the Internet, and change Connect Using to Static IP Address. You'll have to fill in the fields using addresses appropriate for your network.