[jdev] STUN - ( was: voicechat again)

Richard Dobson richard at dobson-i.net
Wed Mar 3 07:20:26 CST 2004

> Hmm...this is interesting.  I was under the impression that 90% of all
> home NAT devices would be either Full Cone or (Port) Restricted Cone.  Not
> sure why I thought that though.  I know we have Symmetric NAT's at work,
> but they are used to connect our outsourced customers networks to our own
> - not much VoIP happening there.

Well my MSN messenger 6 at home tells me I am using a symmetric NAT, and it
also does so at work via both of our ADSL lines, one a watchguard firewall,
and one an ADSL router/firewall which as luck would have it has UPnP.

> WinStun (http://www.vovida.org/applications/downloads/stun/) tells me I
> have a Cone NAT (So I'm alright Jack!).  Have you run it on your machine?
> I'd be interested to see what it says.  Also Skype cuts though my NAT
> router like a hot knife though butter, so if they are using STUN it seems
> to work for everyone I know who has tried it.

Ill check it out later.

> Well - a couple of problems with this.  For those outside the US, there
> may not be much choice as the IP allocation in some countries can be
> "somewhat less" than other countries - as I understand it.  Also, if you
> are Joe/Jane Sixpack, you may have no idea that your ISP has installed a
> cascading NAT - all you may know is that your Jabber telephony stopped
> working, and you might be tempted to blame the product rather than your
> ISP, which is letting you surf the web and check your email just fine.

Im in the UK and IP allocation seems fine but I expect it is worse in other
countries, but surely a client would be able to present the user with a
message indicating that it cannot connect because of problems with the ISP,
so users wouldnt be tempted to blame the software.


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