[dcc2] UDP Nat2Nat Traversal

[Dan Smith]

Hi Trent,

The great thing about a publication system for connection negotiation is 
that you can publicize if you support a certain protocol / type of 
connection negotiation.  This also allows client authors to implement only 
what they feel their users need.  I am sure some clients want to address 
the NAT transfer issue, and we should decide on some methodology/tokens for 
creating these types of connections.

First, (this is outside the scope of our drafts) I would like to advocate 
the use of UPNP by clients to open ports for transfers if passive transfers 
or available ports are not present.  A client using upnp can then use the 
normal negotiation process to establish a connection.  If that fails...

I think that Nat-Nat traversal + TFTP (or other standard udp file transfer 
protocol) would work well for file transfers when no other option is 
present. The type of available traversal methods could be specified as 
values of the NAT token during publication.  Peter mentioned STUN, any 
other methods or protocols available?

cheers!
Dan

At 08:26 AM 4/27/2004 +0800, you wrote:
>Hi,
>
> > I think you're referring to actually transferring files using UDP?
>Yes :)
>
> > If
> > so, I think it might be a lot more hassle than it's worth.
>Well, possibly, I thought I'd suggest the idea as its usefull..
>
> > In addition
> > to handling ACKs, you also need to handle packet ordering;
> > just
> > because one UDP packet is sent before another doesn't mean the packets
> > are going to arrive on the other end in that order.
>
>*nod*
>
> > Basically we would
> > have to re-invent TCP (transmission control...), but luckily that has
> > already been taken care of :).
>yes, however this requires that one of the machines have a public IP
>address, and this is often not the case.
>
>I am also aware of the complexities of transfers over UDP, however in
>some cases its usefull, although, I guess, for general IRC clients it
>might be more of just a hassle over the potential gain.
>
>Cheers,
>Trent
>Bur.st
>
> > -----Original Message-----
> > From: dcc2-bounces at dcc2.org [mailto:dcc2-bounces at dcc2.org] On Behalf
> > Of Trent Lloyd
> > Sent: Monday, April 26, 2004 5:23 AM
> > To: dcc2 at dcc2.org
> > Subject: [dcc2] UDP Nat2Nat Traversal
> >
> > Hi Guys,
> >
> > I wonder if you should consider a UDP implementation in DCC2 that will
> > allow people behind NAT/Firewall/Routers to still connect to each
> > other.
> >
> > It will need a little more love than a TCP connection obviously
> > (because you need to handle the ACKs etc) but I don't see why you
> > can't do something similar to TFTP.
> >
> > With many people having DSL/Cable routers these days, unconfigured
> > port forwarding is often a problem, as well as those behind NAT at
> > home, work, school, etc.
> >
> > Just wondering if it had been covered, and if it's worth my wild
> > writing it up in detail....
> >
> > Cheers,
> > Trent
> > Bur.st
> >
> > --
> > Trent Lloyd <lathiat at bur.st>
> > Bur.st Networking Inc.
> >
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---------------------------
Dan Smith
+1 608-213-2867
Algenta Technologies, LLC