[Asterisk-Users] Is SKYPE a threat or should we dosomething(together)

Aza aza at azaclauson.com
Tue May 17 14:17:38 MST 2005


> -----Original Message-----
> From: asterisk-users-bounces at lists.digium.com [mailto:asterisk-users-
> bounces at lists.digium.com] On Behalf Of Cameron Schaus
> Sent: 17 May 2005 21:18
> To: Asterisk Users Mailing List - Non-Commercial Discussion
> Subject: Re: [Asterisk-Users] Is SKYPE a threat or should we
> dosomething(together)
> 
> > In reality skype is marketing hype (p2p when its really direct between
> > the two endpoints, but p2p is a marketing term because everyone can feel
> > like a rebel for using it) and a proprietary voip protocol.
> 
> In reality, how can 2 skype users, both behind firewalls, communicate
> with each other without opening ports?  By using another node (peer)
> on the skype network that is not behind a firewall (well, blocking
> skype ports).  If you are on skype and not blocking skype ports, then
> you are likely relaying other skype users phone calls. [1]
> 
> In this way, you could call skype p2p.

The thing that has made Skype such a success is how easy it is for people to
use. 

I spend a lot of time on the phone talking customers through connecting up
SIP or IAX softphones and in most cases they have managed to get Skype
working by themselves.

What makes Skype work so easily, apart from its intuitive interface (that
can be copied), is the fact that it can tunnel through TCP port 80 or more
importantly through a HTTPS proxy (which means it will get through just
about every default firewall configuration) and it seems to be able to deal
with NAT is a very sophisticated way! 

(As an aside I have heard of some countries preventing the use of Skype by
blocking access to the Skype web site payment pages because it is too
difficult to block the traffic from the Skype clients.)

While it would be nice for Asterisk to integrate somehow with the Skype
network (a possibly fruitless effort since Skype can continually upgrade
their software to break any such attempts as they did with FastTrack or
Kazaa, can't remember which) what would be even better is a softphone that
is as easy to use with Asterisk as the Skype client is with the Skype
network. 

A softphone out of the box that attempts to traverse firewalls by going
through HTTPS proxies to get to Asterisk is what's needed! I know you can do
it by using something like openvpn to set up a tunnel but this is not
something most people have the time or knowledge to set up.

I don't know enough about the internals of the IAX and SIP channels in
Asterisk but I suspect it would be a big enough job to convert one of them
to use TCP and thus allow Asterisk to listen on TCP 443.

And then of course there is the NAT handling in Skype which seems to be
highly sophisticated, once again probably as a result of their previous work
in the p2p space, and seems to be a fair bit ahead of Asterisk's NAT
handling abilities.

Aaron





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