# Trying To Block a range of IP addresses

I am struggling trying to understand the CIDR Notation. I understand that

217.160.0.0/16 wil reference all if the addresses from 217.160.0/0 to 217.160.155.255

but I only want to block 217.160.152.0 - 217.160.152.255 I can’t figure out if that is 217.160.152.0/32 or /8

I have tried /32 to attempt to block the German miscreant who is accessing all many of my sites in bursts of ~10 access per second for ~5 seconds at a time.
Sorry to be so dumb.

217.160.152.0/24

217.162.152.34/8 = 217.0.0.0 - 217.255.255.255
217.162.152.34/16 = 217.162.0.0 - 217.162.255.255
217.162.152.34/24 = 217.162.152.0 - 217.162.152.255
217.162.152.34/32 = 217.162.152.34

Lots of resources to explain, or calculate these, if you Google for it.

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Try an online CIDR calculator - we use CIDR to IPv4 Address Range Utility Tool | IPAddressGuide - they do an IPV4 and an IPV6 one

Given the ASN that the range in question belongs to I would be tempted block that ASN completely, we do

Thanks… how do I block the whole of the ASN? and who does it belong to? I couldn’t get much out of IPLookup except cskutterfebsscr11.ext.server.lan

Thanks SJR … I did google it but had difficulty understanding – I didn’t find a simple explanation like you have helpfully given.

Cloudflare radar is the easiest lookup tool…