RE: [Ietf-behave] RE: [Sip] draft-takeda-symmetric-nat-traversal ??

I've removed from the SIP mailing list and kept it in BEHAVE.

I agree with Dan that the mechanism is brittle. However, there is
some good information in there. 

In particular, I find Table 6.3.1 a nice way to reconcile the
categories of NAT behavior we have in BEHAVE with the "old" 
terminology (Cone, Symmetric, etc). Might be a good idea to think
about a similar format. I'll think about it.

> -----Original Message-----
> From: ietf-behave-bounces@xxxxxxxxxxxxxxxxxxx 
> [mailto:ietf-behave-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of Dan Wing
> Sent: Wednesday, September 29, 2004 21:10
> To: Vikram Bhuskute; sip@xxxxxxxx
> Cc: takeday@xxxxxxxxx; IETF Behave Mailing List
> Subject: [Ietf-behave] RE: [Sip] 
> draft-takeda-symmetric-nat-traversal ?? 
> 
> 
> Thanks for bringing that I-D to the group's attention.  I, 
> for one, hadn't seen it.
> 
> Section 8.1 is where the meat is, and it says:
> 
>    ...
>    If
>    the port allocation rule of the other endpoint is a symmetric type,
>    the endpoint needs either to record the source port number of an
>    incoming packet or to predict a port number that the symmetric NAT
>    will assign, with a MAPPED-ADDRESS obtained from the other 
> endpoint.
>    ...
> 
> which I agree isn't a good mechanism, especially with a large 
> NAT.  It could work just fine on a small, residential NAT 
> which isn't processing much new traffic (and thus it is, in 
> theory, possible to guess the next port number it will assign 
> for the next mapping).
> 
> This technique is too fragile for my blood.
> 
> 
> There is a lot of other good information in this Internet 
> Draft, though; I hope we can incorporate some of it into the 
> BEHAVE work if the author is willing.
> 
> -d
> 
> > -----Original Message-----
> > From: sip-bounces@xxxxxxxx [mailto:sip-bounces@xxxxxxxx]On 
> Behalf Of 
> > Vikram Bhuskute
> > Sent: Wednesday, September 29, 2004 4:12 AM
> > To: sip@xxxxxxxx
> > Subject: [Sip] draft-takeda-symmetric-nat-traversal ??
> >
> >
> > Hello all,
> >             While searching for NAT traversal solution i 
> came across a 
> > draft  "draft-takeda-symmetric-nat-traversal-00.txt"
> >             from url ( 
> > http://cnscenter.future.co.kr/resource/ietf/ind-draft/draft-takeda
> > -symmetric-nat-traversal-00.txt)
> >
> >            It proposes some solution for Symmetric NAT 
> based on some 
> > Prediction .....?  It dosent seem reliable ... !!!
> >           (however it gives  glimps on type of Symmetric NATs )
> >
> >            Is it still a matter of further research ? or 
> the concept  
> > is not well accepted ?
> >
> >           thanks in advance
> >
> >  vikram
> >
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