Knowledge base Network compatibility
The Mac’s IP address must conform to RFC 1918, which means its IP must start 10.x.x.x or 172.16.x.x to 172.31.xx, or 192.168.x.x. An exception is when the local IP address is the same as the public IP address. Don’t worry, most local networks are fine. Content caching requires the Mac to be powered up, not powered down in sleep mode.
There are often multiple Apple devices in homes and offices. You may have an iMac and a MacBook, you, your partner and teenage kids may all have iPhones, maybe even a couple of Apple TVs, too. Updates for devices are sometimes large and the internet gets bogged down updating each device separately.
The solution is to download updates once, store them on the Mac and let other devices access them over the network. Transferring big files over a local network is much faster than downloading them from the internet. It sounds complicated, but it is very easy and has been in macOS for some time.