[jdev] STUN - ( was: voicechat again)

Michael Brown michael at aurora.gen.nz
Wed Mar 3 06:51:33 CST 2004

>> Yes - this is true (to a point).  But it doesn't have to be
>> an either/or I think.  Those with UPnP enabled routers can
>> use UPnP, those with non-uPnP routers could use STUN.
> Sure course, the only problem I see is that all NAT's ive
> ever used have all been symmetic NAT's are there many NAT's
> that will work with STUN even out there?.

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.

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.

>> Where UPnP falls down (I am told) is where you have cascading NAT's
>>  - if your ISP has NAT'ed your connection at their end (to save
>> IP addresses etc), your UPnP ADSL router won't help you much.
> Sure, but in that case STUN wouldnt help you either would it?

Actually I think it does - if I'm reading this
(http://corp.deltathree.com/technology/nattraversalinsip.pdf) document

> If you are in this situation then you are pretty mcuh stuffed,
> anyone in this situation should really consider moving ISP's.

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.


More information about the JDev mailing list