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<p>Hi,<br>
</p>
<br>
<div class="moz-cite-prefix">On 2/23/17 12:11 AM, Shane Kerr wrote:<br>
</div>
<blockquote
cite="mid:20170223001128.1027432e@pallas.home.time-travellers.org"
type="cite">
<pre wrap="">Roland,
At 2017-02-22 20:57:34 +0000
Roland Perry <a class="moz-txt-link-rfc2396E" href="mailto:roland@internetpolicyagency.com"><roland@internetpolicyagency.com></a> wrote:
</pre>
<blockquote type="cite">
<pre wrap="">In message <a class="moz-txt-link-rfc2396E" href="mailto:4C47D72B-8A25-4CFE-AF61-B7347F726579@ripe.net"><4C47D72B-8A25-4CFE-AF61-B7347F726579@ripe.net></a>, at 12:32:33
on Thu, 16 Feb 2017, Chris Buckridge <a class="moz-txt-link-rfc2396E" href="mailto:chrisb@ripe.net"><chrisb@ripe.net></a> writes
</pre>
<blockquote type="cite">
<pre wrap="">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)
</pre>
</blockquote>
<pre wrap="">
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.
</pre>
</blockquote>
<pre wrap="">
IP+port, right?</pre>
</blockquote>
<br>
Right. And the big issue in this report <b>isn't</b> how it
impacts the telco/routing aspects of an ISP, but how it may impact <b>any</b>
content provider by requiring logging changes to include at least
src IP+port and possibly the entire 5-tuple. Here's the relevant
content from that document:<br>
<br>
<blockquote type="cite">
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<div class="page" title="Page 6">
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<ul style="list-style-type: disc">
<li style="font-size: 12.000000pt; font-family:
'SymbolMT'">
<p><span style="font-size: 12.000000pt; font-family:
'TimesNewRomanPSMT'">In order to be able to trace
back an individual end-user to an IP address on a
network using
CGN, law enforcement must request additional
information</span><span style="font-size:
8.000000pt; font-family: 'TimesNewRomanPS';
font-weight: 700; vertical-align: 6.000000pt">3 </span><span
style="font-size: 12.000000pt; font-family:
'TimesNewRomanPSMT'">from content providers via
legal
process:
</span></p>
<p><span style="font-size: 12.000000pt; font-family:
'CourierNewPSMT'">o </span><span style="font-size:
12.000000pt; font-family: 'TimesNewRomanPSMT'">Source
and Destination IP addresses;<br>
</span><span style="font-size: 12.000000pt;
font-family: 'CourierNewPSMT'">o </span><span
style="font-size: 12.000000pt; font-family:
'TimesNewRomanPSMT'">Exact time of the connection
(within a second);
</span><span style="font-size: 12.000000pt;
font-family: 'CourierNewPSMT'">o </span><span
style="font-size: 12.000000pt; font-family:
'TimesNewRomanPS'; font-weight: 700">Source port
number.
</span></p>
<p><span style="font-size: 12.000000pt; font-family:
'TimesNewRomanPSMT'">However, the lack of harmonized
data retention standard requirements in Europe</span><span
style="font-size: 8.000000pt; font-family:
'TimesNewRomanPSMT'; vertical-align: 6.000000pt">4 </span><span
style="font-size: 12.000000pt; font-family:
'TimesNewRomanPSMT'">means that
content service, Internet service and data hosting
providers are under no legal obligation to
retain this type of information, meaning that even a
more elaborate request from LEA would
not yield useable information from the provider.
</span></p>
<p><span style="font-size: 12.000000pt; font-family:
'TimesNewRomanPS'; font-style: italic">Regulatory/legislative
changes would be helpful to ensure that content
service providers
systematically retain the necessary additional data
(source port) information to allow law
enforcement and judicial authorities to identify one
specific end-user among the thousands of
users sharing the same public IP address</span><span
style="font-size: 12.000000pt; font-family:
'TimesNewRomanPSMT'">.
</span></p>
</li>
<li style="font-size: 12.000000pt; font-family:
'SymbolMT'">
<p><span style="font-size: 12.000000pt; font-family:
'TimesNewRomanPSMT'">As some content providers in
Europe do store the relevant information but some
others do not
practical solutions can be sought through
collaboration between the electronic/Internet?
service
providers and law enforcement using already
established channels for cooperation such as the
EU Internet Forum.
</span></p>
</li>
</ul>
</div>
</div>
</div>
<title></title>
</blockquote>
<br>
Note that [3] refers to RFC 6302 from June of 2011, and the abstract
of that document makes plain the problem:<br>
<br>
<blockquote type="cite"> In the wake of IPv4 exhaustion and
deployment of IP address sharing<br>
techniques, this document recommends that Internet-facing
servers log<br>
port number and accurate timestamps in addition to the incoming
IP<br>
address.<br>
</blockquote>
<br>
But here's your bog standard apache log line:<br>
<br>
<b>10.11.12.13</b> - - [23/Feb/2017:08:50:18 +0100] "GET / HTTP/1.1"
200 67442 "-" "Mozilla/5.0 (Windows NT 6.1; WOW64; rv:40.0)
Gecko/20100101 Firefox/40.1"<br>
<br>
Note what is <b>NOT</b> there. It is easy enough to change this
with the LogFormat statement in Apache. However, you do so at your
peril if you have any tools consuming those logs. The risk is
probably <b>not</b> to the Akamais of the world, but to any small
business that decided to a server on their own, and probably has NO
idea as to what the legal requirements are.<br>
<br>
<blockquote
cite="mid:20170223001128.1027432e@pallas.home.time-travellers.org"
type="cite">
<pre wrap="">
</pre>
<blockquote type="cite">
<pre wrap="">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.
</pre>
</blockquote>
<pre wrap="">
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.)
</pre>
</blockquote>
<br>
Many operators using CGN are <b>already</b> required to retain this
mapping. There are some tools out there to reduce the data
requirement, such as bulk assignment. The problem here is that the
ISP using CGN actually changes the game for the end site.<br>
<br>
Eliot<br>
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