IP address ranges

Hi! I would like to add IP ranges to the whitelist, but I receive an error “199.27.128.0-199.27.135.255 is not a valid ip.”
I tried to add spaces before and after dash but still nothing: “199.27.128.0 – 199.27.135.255 is not a valid ip.”
Please help. I can’t go with IP list beacuse it has enormous size (251040 addresses).

Why CIDR is not supported?

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