Addressing plan exercise for our IPv6 course

Tue Jul 27 19:34:40 UTC 2010

On Jul 27, 2010, at 12:05 PM, Akyol, Bora A wrote:

> Please see comments inline.
> 
> 
> On 7/22/10 10:13 PM, "Owen DeLong" <owen at delong.com> wrote:
> 
>> In all reality:
>> 
>> 1.      NAT has nothing to do with security. Stateful inspection provides
>>        security, NAT just mangles addresses.
> Of course, the problem is that there are millions of customers that believe
> that NAT == security. This needs to change.
>> 
>> 2.      In the places where NAT works, it does so at a terrible cost. It
>>        breaks a number of things, and, applications like Skype are
>>        incredibly more complex pieces of code in order to solve NAT
>>        traversal.
> 
> I look at this as water under the bridge. Yep, it was complicated code and
> now it works. I can run bittorrent just fine beyond an Apple wireless router
> and I did nothing to make that work. Micro-torrent just communicates with
> the router to make the port available.
> 
It's only water under the bridge for IPv4. If we start putting NAT66 into play,
it will be the same thing all over again.

Additionally, it's only water under the bridge for existing applications. Each
new application seems to go through the same exercise because for some
reason, no two NAT gateways seem to have exactly the same traversal
requirements and no two applications seem to implement the same set
of traversal code.

> 
>> The elimination of NAT is one of the greatest features of IPv6.
>> 
>> Most customers don't know or care what NAT is and wouldn't know the
>> difference between a NAT firewall and a stateful inspection firewall.
>> 
>> I do think that people will get rid of the NAT box by and large, or, at least
>> in IPv6, the box won't be NATing.
>> 
>> Whether or not they NAT it, it's still better to give the customer enough
>> addresses that they don't HAVE to NAT.
>> 
>> Owen
>> 
> 
> Of course, no disagreement there. The real challenge is going to be
> education of customers so that they can actually configure a firewall policy
> to protect their now-suddenly-addressable-on-the-Internet home network. I
> would love to see how SOHO vendors are going to address this.
> 
Not so much... SOHO gateways should implement stateful inspection
with the same default policy a NAT box provides today...

1.	Outbound packets create a state table entry.
2.	Inbound packets are only forwarded if they match an existing
	state table entry.

Pretty simple, actually.

Owen