Python Magazine

[Carlos Nepomuceno]

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> Date: Sun, 26 May 2013 15:17:11 +1000
> Subject: Re: Python Magazine
> From: rosuav at gmail.com
[...]
>> Blocking a whole network (/65) is totally undesirable and may even become illegal.
>
> Blocking a /64 is exactly the same as blocking a /32 with NAT behind
> it. And how could it be illegal? I provide service to those I choose
> to provide to.

I'm not a lawyer, so what I say about the IP blocking legal matter is just an opinion. I'm not responsible for any damages it may cause to anyone!!! lol

It just looks like those damn software disclaimers, doesn't it? ;)

Depending on the jurisdiction things maybe very different.

I've been told that in California it is really illegal to block IP addresses without a court order. Any Californians available to confirm that?

"The sender of information over the Internet is the "owner" of both the information and the IP address attached to the information. The practice of IP address blocking "records" the IP address and "destroys" the information in the message "without the intent or permission of the owner of the information," and "usurp[s] the normal operation of the . . computer network." Software designed to record IP addresses and use them to block messages is thus a "computer contaminant" according to the above definition. "

Source: http://im-from-missouri.blogspot.com.br/2007/05/ip-address-blocking-is-illegal-in.html


Also check California Penal Code Section 502, "Unauthorized Access To Computers, Computer Systems and Computer Data":
http://www.leginfo.ca.gov/cgi-bin/displaycode?section=pen&group=00001-01000&file=484-502.9


The problem is serious and there are many cases, such as:
http://www.theregister.co.uk/2011/10/13/dutch_isp_accuses_spamhaus/


>> Currently it may not only happen at the target of the DDoS attack, but be spread all over the internet where block lists are enforced.
>>
>> I don't expect that to happen and if it happens I'm surely in favor of protection against this type of 'solution' because it will block not only malicious clients but potentially many other legitimate clients.
>
> Banning a wide netblock is of course going to lock out legit clients.
> But IP rotation means that can happen anyway. You block a single IPv4
> address that right now represents an abusive user; that user
> disconnects and reconnects, gets a new IP, and someone else gets the
> other one. Can happen all too easily. That's why IP-banning is at best
> a temporary solution anyway.

IP blocking isn't a perfect solution as you have confirmed. That's why using it is so problematic. It may hurt legitimate clients and other unrelated ones, while the "abusive user" as you said gets out unharmed.