Connecting AirPlay from Mac on Ethernet and Wi-Fi

Peter Davis4 wrote:

So, its a wifi (5g) modem to the TP link switch to the TB3 dock to my Mac.

Just to make sure we are on the "same page," the terms "modem" and "router" could mean the same thing. I believe folks outside the US refer to them a modems. Whereas, in the US, they are called routers. In the US, a modem is a different device that you would use only if you have a single device to connect to the Internet.

Regardless, I am assuming that your "modem" is a combination device that includes a modem, router, Ethernet switch, and wireless access point, all in one device. It may help if you can provide us with the make & model so we have a better idea on what we are working with.

If I understand you correctly, you have TP Link (Ethernet) switch that is directly connected this modem, and in turn, you have an Ethernet cable running between this switch and a dock that you connect your Mac to.

I reset the modem & put it into 'bridge' mode

This basically stopped most of my internet from working. Most but not all websites would not load. But the network was visible & I could join. I couldn't get airplay working like this.

So, I took the modem out of Bridge mode, and I have internet again, both wifi and ethernet.

Placing your modem into bridge mode disables a number of services (in particular: NAT & DHCP) which are required when you need multiple devices on your local network to gain access to the Internet. As you saw, placing it into bridge mode "broke" the Internet ... and should not be necessary for the AirPlay issue.

I can see both the wifi & TB3 are on the same subnet mask : 255.255.255.0

Router ip shows the same for both devices

Although the subnet mask is important, that's not I was referring to when I mentioned that both network interfaces need to be on the same subnet. To be on the same subnet, both interfaces should be using a similar IP address. For example, if your network's modem is providing local IP addresses in the 192.168.1.x range, then to be on the same subnet, each of those interfaces should be in that same range, i.e., Ethernet on 192.168.1.10 & Wi-Fi on 192.168.1.20. Note that it doesn't matter what the last number is, although they should not be the same.

Let's try something simple. Temporarily disconnect your Mac from the dock. Insert the Ethernet cable that was connected to the dock to the Mac instead. Temporarily disable Wi-Fi on the Mac, and then, test that the Mac can still access the Internet. If successful, try using AirPlay from the Mac. Please let me know your results.

My Mac is connected to both Ethernet and Wi-Fi, with Ethernet being the primary network: Change the order of the network services your Mac uses - Apple Support. I have no issues broadcasting from the Mac using AirPlay.

I would suggest making your Ethernet network the primary network and Wi-Fi the secondary.

Typical setup

• broadband connection to home
• when then goes into your home router (this may be the same device, or it maybe separate)
• Ethernet switch plugged into router
• CalDigit TS3 plugged into Ethernet switch.

• Typically WiFi is also part of the home router.
• If you have more than 1 WiFi access point, then every additional WiFi access point, down stream from the broadband connect home router, these additional WiFi routers have to be in "Bridge" mode as Rudegar says.
  • This would be automatic if you are using a Mesh network.
  • If using WiFi routers as WiFi extenders, then they MUST be configured manually for Bridge mode.
    • Some WiFi routers can be put into Bridge mode with a setting that says "Bridge" mode.
    • Some require you to disable the router's "DHCP server", and that puts it into Bridge mode
    • Some also require disabling the "NAT server"

If you are using multiple WiFi routers, without putting the ones down-stream from the router talking to the broadband, then you have multiple LAN subnets that are NOT talking to each other. Bridge mode puts everyone on the same subnet, and everyone sees everyone else.

Finally, many WiFi routers today offer a "Guest" network. The router will intentionally "Isolate" the Guest network from the rest of your home network, so that you guests (Aunt Gracie and Uncle George) cannot see the rest of the network traffic in your home. You do not want your AirPlay device using the Guest network.

I personally have an "eero" Mesh network, but years ago, I also had multiple WiFi routers as extenders, and the additional WiFi routers were all put into Bridge mode. This system worked fine. And by years ago, I mean I started doing this in the early 2000's.

I also have a CalDigit TS3 connected via Ethernet to a TP-Link Ethernet switch in the basement, that is connected to the main "eero" Mesh network router, which is connected to my cable modem. I jump between WiFi and Ethernet with my devices all the time. Everyone can see everyone else. Macs, iPhones, iPads, network multi-function printer, Apple TVs, the TV which have Ethernet connections, the smart lights, smart outlets, the Ring Doorbells, the WiFi connected sprinkler system controller, the 2 Synology NAS boxes, I most likely forgot a few items, but you get the Idea. A properly setup home network will allow all the devices to see each other.

ones wifi router needs to be configured to bridge 2.4Ghz wifi and 5Ghz wifi and wired eathernet for devices to communicate across the medias

how one goes about configuring that differ from wifi router to wifi router, most has a means to configure it using a browser or an mobile app

Since you verified that AirPlay is working with Wi-Fi, I'm expecting that it should work with just an Ethernet connection. If it does, it is pointing to the dock that you are using. If it does not, then there may be something amiss with your Mac's Ethernet configuration.

This might be because of the switch and how it connects to the rest of the network.

I use an Asus Wi-Fi router that has Ethernet ports. I assume that my router makes sure Ethernet and Wi-Fi are consistent.

I have no experience at all in configuring networks. I’m going to ask other contributors to join this discussion.

SIM card? Do you get your Internet service via a cellular provider? That is, is this a cellular modem, and not one that gets Internet from cable, fiber, or satellite?

As far as the "missing" Ethernet port on your Mac, one option is to get a USB-C to Ethernet adapter. If nothing else, it could come in handy in the future.

Sorry, but I don't have a "What next?" to try. Based on what you provided, the issue does appear to be related to using this TB3 dock with your Mac. I suggest contacting the dock's manufacturer's support site to see if they can offer any assistance with this matter. I'm sorry I couldn't help you with a solution,