- What I did

Avoid this sort of confusion (from the community Slack) ...

I think I have found a bug in docker (Docker version 27.3.1, build ce12230)
My network at home is a /20 not because I actually need the numbers of devices but to be able to give a complete /24 range to a macvlan while at the same at the same time keeping my devices on their normal ip's ( were a /24 prior )
so my range on my network is from 192.168.80.1-192.168.95.254
And when I try to create the macvlan it says

$ docker network create -d macvlan --subnet 192.168.80.0/20 --gateway 192.168.80.1 --ip-range 192.168.83.1-192.168.83.254 -o parent=eno1 macvlan-test
no matching subnet for range 192.168.83.1-192.168.83.254

- How I did it

Check that --ip-range is a CIDR address, to produce a better error message.

The original error message was from the CLI, but it used subnetMatches(s,r) to check that the range was ok - that function tries to deal with r being a single address as well as a subnet, so it missed the problem. (Validation at the daemon end of the API is already ok.)

- How to verify it

Updated test, and ...

# docker network create -d macvlan --subnet 192.168.80.0/20 --gateway 192.168.80.1 --ip-range 192.168.83.1-192.168.83.254 -o parent=eno1 macvlan-test
invalid CIDR address: 192.168.83.1-192.168.83.254

- Description for the changelog

n/a