[cooperation-wg] Europol Communication on Carrier-Grade NAT

Roland,

At 2017-02-22 20:57:34 +0000
Roland Perry <roland at internetpolicyagency.com> wrote:

> In message <4C47D72B-8A25-4CFE-AF61-B7347F726579 at ripe.net>, at 12:32:33 
> on Thu, 16 Feb 2017, Chris Buckridge <chrisb at ripe.net> writes
> 
> >LEA interest in reducing the use of CGN also came up for discussion at
> >the recent RIPE NCC Roundtable Meeting for Governments and Regulators
> >(held in Brussels on 24 January)  
> 
> The UK's approach, as expressed in the 2016 IP[1] Act, is not to 
> prohibit CGN, but require operators to log who was using which IP, when.

IP+port, right?

> This is exactly the same as when Internet access was primarily by 
> dial-up to banks of modems, and customers shared the IP Address of the 
> modem. The ISPs were expected to log who had been online at a specific 
> IP address at a specific time.

It's not exactly the same, because a dial-up session was expected to be
several minutes or even hours. A single IP+port may be used for less
than a second.

Plus there is likely an extra layer of indirection. A NAT device may
know the customer private IP address and the public IP address, but
might not necessarily have access to the database which assigned the
customer to the private IP address. So that data also needs to be
logged & correlated.

If LEA are expected to pay for all of this extra storage and
processing - or even if it just makes investigations slower - then I
can easily understand why they would want to reduce the use of CGN. (If
that cost gets eaten by ISP, then the push will naturally go towards
fewer CGN without any encouragement by the LEA.)

Cheers,

--
Shane
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