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<p class="MsoNormal"><span style="font-size:11.0pt">Hello NANOG,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">We are discussing internally and wanted to get more opinions and especially more data on what are people actually doing.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">We are running an ISP network with about 150K fixed broadband users, running dual stack (IPv4 behind CGNAT).<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">On the ISP network IPv6 is simply routed, and is firewalled on the CPE.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">This network added mobile services about a year ago, also dual stack (we have no control on the mobile devices so we were too concerned to choose IPv6 only access).<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">We have an ongoing discussion about Gi firewall (adding a firewall between the subscribers and the internet, allowing only subscriber initiated connections), for the IPv6 traffic.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">The firewall is doing very little security, the ruleset is very basic, allowing anything from subscribers to the internet and blocking all traffic from the internet towards the subscribers.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">We have a few rules to limit the number of connections per subscriber (to a relatively high number) and that is it.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">One of the arguments in favor of having the firewall is that unsolicited traffic from the internet can “wake” idle mobile devices, and create signaling (paging) storms as well as drain user batteries.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">On the other hand, allowing only subscriber initiated traffic is mostly achievable using ACLs on the mobile core facing routers, or is it with the growing percentage of UDP traffic ?<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">BTW – I don’t mention IPv4 traffic on the mobile network as it’s all behind CGNAT which don’t allow internet initiated connections.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">Anyway, we are very interested to know hear more opinions, and especially to hear what are other mobile operators do.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">Regards<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">Amos<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
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