The expression "5.188.210.0/100" is not an IP range. It's something invalid that doesn't make sense. The format IP/INTEGER is called a CIDR notation. Since you're talking IPv4 addresses the integer part can be 1 (all IP addresses) to 32 (just the one IP address you specified). That makes sense since IPv4 addresses are 32-bit integers and the integer part of a CIDR notation is a bit mask. Using an 100-bit mask for a 32 bit integer is an unspecified operation, therefore your input is considered junk and silently discarded when evaluating IP blocks.
If you meant to block 5.188.210.0 to 5.188.210.100 you should write it as 5.188.210.0-5.188.210.100 instead. There is no single CIDR notation which would cover all 100 IP addresses.
If you meant to block all addresses from 5.188.210.0 to 5.188.210.255 you can write it either as 5.188.210.0-5.188.210.255 or 5.188.210.0/255.255.255.0 or 5.188.210.0/24
If unsure please use a CIDR calculator tool such as https://www.ipaddressguide.com/cidr
Nicholas K. Dionysopoulos
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