If you live in a single-family home and your Sail Internet connection is using a rooftop radio, then we do not need to know the MAC address of your router. In this case, we use the rooftop radio information to authenticate. You can connect any router you want to the rooftop radio (via the Power-over-Ethernet (PoE) adapter that is located inside your home).
If you live in a condo or apartment complex, then we have to keep a record of the MAC address of your router, because we use it for authentication purposes. We specifically need the MAC address of the WAN (or Internet) port of the router. For most models, this is written on the back of the router. There are a few brands for which the MAC address of the WAN port is slightly different than the MAC address written on the back of the router. You can confirm the MAC address of the WAN port from the router management GUI or app. If you are having trouble finding the MAC address, contact us and we will help.
You should not connect a switch device (or a WiFi access point) directly to the Sail cable. This may sometimes happen by accident, because WiFi routers can be configured to operate as access points. This is a security risk for your home network's devices, because they are then directly connected to the internet and may be using a "public" IP address. The correct home network configuration is to have a router separating your home devices from the internet, where only your router has a public IP address and the home devices use private IP addresses.