IPv6 news

Thu Oct 13 00:48:53 UTC 2005

On Wed, 12 Oct 2005, Sean Figgins wrote:

> On Wed, 12 Oct 2005, william(at)elan.net wrote:
>
>> addresses. But of those "few" many are those doing P2P sharing
>> especially with BitTorent and this application requires open port
>> on the user end, so in fact P2P and BT may prove to be the cornerstone
>> to getting wider use of IPv6 after we ran out of v4 space...
>
> Both BT and other P2P protocols are perfectly happy behind NAT.  There are
> a few that seem to prefer that they have a non-natted address, or use some
> port forwarding.

P2P protocols will work behind NAT only for clients. But if you want to
have distributed indexes and distributed content servers (which is what
P2P aims at) you need to have those who provide content to have open 
ports for outsiders to connect to. With NAT this is achieved by opening 
those specific ports which is fine for when you have home firewall but it 
would not work if you do not control the NAT box.

But its possible to use technique where only index server has to have 
an open port and than require all content server clients to keep open 
connection to it and use that to direct them to connect to new clients
requesing the data - I'm not sure if BT is doing it right now or not.

> Those applications will just need to be fixed if it becomes a common
> practive of handing out NAT addresses to customers.

You can fix some applications but not all and when you're faced with
situations that you do not even control NAT, then you have a problem.

> I think the bigger problem would be that of a larger company running 
> out of RFC 1918 space, for various reasons.

If its corporate system, they'd also end up using NAT (many already do).
The problem would be for webhosts and ASPs who have no choice but to use 
real ips.

-- 
William Leibzon
Elan Networks
william at elan.net