<div style="font-family:arial,helvetica,sans-serif;font-size:10pt">On Tue, Nov 27, 2012 at 7:44 AM, Dan Wing <span dir="ltr"><<a href="mailto:dwing@cisco.com" target="_blank">dwing@cisco.com</a>></span> wrote:<br>
<div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div class="im">Desires to allow unsolicited inbound IPv6 packets sound great until</div>
the fridge is hacked and the beer is too warm to drink. The blame for<br>
the warm beer will be placed on IPv6.<br></blockquote><div><br></div><div>Well, but isn't that a little like saying that the blame for the accident will be placed on the faster car the customer has bought instead of the carelessness of the driver? I mean, what the question boils down to is:</div>
<div><br></div><div>- In most cases (not always - for example when you plug your computer directly into the cable modem, when you're at a coffee shop or university network, etc. etc.), today's Internet connections offer restricted connectivity because of NAT</div>
<div>- IPv6 removes that restriction and allows full connectivity</div><div>- What should we do? Should we allow this new capability, or should we turn it off because with great power comes great responsibility and we're afraid we might get hurt by it?</div>
<div><br></div><div>In other words, should we take something that was originally a restriction imposed by lack of address space and (permanently?) apply that same restriction to a network that does not have that restriction?</div>
<div><br></div><div>There is a cost to NATs and ALGs. The session timeouts suck, the lack of inbound reachability sucks, the call setup latency sucks, the lack of support for new apps sucks, the session scaling sucks, and so on. Peer-to-peer apps like skype sort of work behind NATs, but at the cost of a loss of quality (e.g., when you have to go through a third-party supernode and your call quality goes down the drain). In IPv4, NATs and ALGs are all we have, but in IPv6 we have the option of doing better.</div>
<div><br></div><div>There's also a security advantage, but as others have said, the security advantage provided by NATs has eroded over time. Attacks and malware moved away from port scans and connection attempts a very long time ago. They now reside at the application layer, conveniently protected by HTTPS, where no network firewall will ever find them. (That's Erik's 80% number.)</div>
<div><br></div><div>So at the end of the day it comes down to what you think your customers would want the extra aggravation in exchange for the extra security. If you asked the customer "would you like your skype calls and video chats to work better, or would you like a double layer of protection from some attacks that aren't really today's main focus?", what would the answer be? Can you give the customer that choice, or are you obliged to pick one answer for everybody?</div>
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