Airport Time Capsule

Why does my Time Capsule need a WAN connection to the router?

Apple designed the Time Capsule to be a WiFi router with a built in hard drive. Since a router needs to connect to a modem or another router using an Ethernet cable connection, the Time Capsule also needs to connect to the network in this way.

If you already have a WiFi router, you have several different configuration options for the setup of the Time Capsule.

1) The Time Capsule can be set up to provide an additional WiFi network that you might use for "guests". You can use the Time Capsule WiFi.....or.....your existing WiFi to back up to the Time Capsule.

2) If you don't need another WiFi network, then you can turn off the WiFi function on the Time Capsule and use it as a simple wired hard drive with your existing WiFi router.

You need to understand the Time Capsule is a dual device.. it can be a router or a purely backup device in your network.. with wireless. It does not need a WAN connection.. but it must be connected to the network. In bridge mode as most people will use them.. it does no routing and the WAN port is actually allocated to LAN.. so there is no WAN at all.

But for your device to connect simultaneously to the internet and do backups it must be part of the network.. hence it must be plugged in by ethernet.. In the past apple did allow the TC to work as a wireless client to the network but the results were so poor they stopped that functionality.

You can use it standard alone.. in other words if you wish to have no internet connection and use the TC purely as a wireless backup you can. The problem is you cannot do both backup over wireless and connection to the internet by wireless at the same time in this setup.

If you are prepared to use both wireless and ethernet then it is possible.

... then it will still be necessary to connect it to your router by Ethernet for connectivity. If that other router is wireless, you can disable the TC's wireless radios as they will not be needed. Your iMac would still connect to the wireless network provided by your other router, and with the TC connected to that same router by Ethernet, it will be able to use it for Time Machine.

For iMac it is very easy really.

Since you have both ethernet and wireless the TC will work far better plugged into ethernet.

Do you use ethernet connection to the main router? If so you can plug the TC in at the Mac end.. which is the same as what Tesserax is saying.. only putting it in different location. ie at the computer end instead of the router end. You then bridge it and plug both the iMac and existing ethernet from router into it.

If you want to use wireless and already have wireless used for internet then you must plug the TC into the router somewhere in the network. But you can also use the TC standalone with a bit of network fiddling. So internet is via wireless and TC is working over ethernet.

Also note for Time Machine backup or use as storage.. the TC is much slower and much less reliable than simply plugging a USB drive into your Mac. Since the Mac is not being carried around it is far better setup.