Hi All,

I am one of the founders of a hobbyist organisation called
wirelesswales.net.

We are building a prototype community WLAN
intranet around South Wales (UK).

The core membership are very much skype evangelists
and would like to use skype as a "proof of concept" service
for the WLAN,

I have successfully used skype at Internet hotspots all around the
world, but (to date) , have not been able to use skype where there is
no internet connectivity. i.e. client to client on a 10.x.x.x/24 style network.

two questions therefore:

1) should i be able to use skype in this scenario (i.e. how "really P2P" is skype's signalling protocol?).

2) If some form of skype "agent" is required to rebroadcast the client
online status, are there any proposals to release this as a stand alone application ?

Many thanks in advance

regards

BB

Skype cannot start in offline network. If you have a large enough network with a small internet connectivity, skype can survive the disconnection of that network.
Skype needs to have at least one supernode in that network, and the reconnecting ones need to be able to find that one.

Search the forum, someone from Skype Staff explained a bit here on the forum!

Hmm...ok, thanks Bonbons!

Looking at this laterally then ...

If I had a firewall between the internet and a local skype host like:



Where the "Blue" interface of the firewall port forwards skype traffic in
to the host in the DMZ , which again port forwards the traffic to the
public internet, perhaps on a different port (effectively a skype proxy)

I can prevent loads of people using the public internet connection by
blocking down the bandwidth available to the DMZ host to provide
enough for signalling / IM functions whilst preventing a voice call
(insufficient bandwidth to make it work out to the internet)

Would such a configuration permit client to client comms WITHIN the
blue clouds ? whilst effectively preventing "Blue cloud" clients making voice calls out to the net (and therefore hogging my ADSL connectivity)
?

regards

BB

(Who, if he had the time, should really sit down with a test config [ethereal, TCPdump, etc ] and test this for real!)

The major difficulty to make this work is probably to convince your Skype on the DMZ to become a SuperNode!
But if you can leave your DSL connection to internet "always on", then this host is not needed! Just open NAT, but limit traffic for any host to a very low speed. (Instant speed, and also over longer time slices => this prevents people from browsing or doing other mad things! [this means 0.5kByte/s peak, max 5kByte in 1min]) This way you could use most of the IM clients as well. To sort them out, you might want to restrict the accessible IP ranges or manipulate the DNS! (e.g. only allow DNS from skype domains, this should be very efficient, don't forget closing port 53 for this!!)

Skype should do all internal calls with direct connections. The major danger is about differing routing tables on the hosts in your WLAN that could make Skype think that he can't have direct communications. (On you picture this would certainly be between Local and Remote community)
To prohibit calls over your DSL to work correctly, you could limit the traffic per IP to less than 1kByte/sec.