Banning an IP address
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whois <ip address>
will typically show you the ip range associated with the IP address (you might have to put some of it intoipcalc
or similar. There are a bunch of websites which will do a WHOIS on the IP address -
If you have banned a single ip address then chances are they can disconnect then reconnect and their ISP will hand them a different IP address. If you ban the entire ip range of an ISP then they would need to proxy through something (VPN) or switch ISP's. Note many of the larger ISP have multiple seemingly unconnected ip ranges as they have gone to their LIR over time to get more allocations.
Simply banning an IP address isn't always the best way forward