Re: How Skype uses the network [was: News item: Blackberry services down worldwide]

[Alex Brooks <askoorb+nanog () gmail com>]

Howdy,

On Fri, Oct 14, 2011 at 8:11 PM, Patrick W. Gilmore <patrick () ianai net> wrote:
> On Oct 13, 2011, at 7:26 PM, Matthew Kaufman wrote:
> > On 10/13/11 3:30 PM, Patrick W. Gilmore wrote:
> > > In fact, Skype, just as a for instance, is worse on hotel wifi as launching the app on a laptop makes you a middle 
> > > node for some conversations.
> >
> > Per the Skype IT administrator guide, a Skype node will not become a supernode unless it has a public IP address 
> > and meets the memory, bandwidth, and uptime requirements. It will not become a relay node unless it has a public IP 
> > address and is directly reachable from the Internet.
> >
> > It is very unlikely that launching the Skype app on a laptop on hotel wi-fi would meet these requirements.
>
> In the last 5 seconds, without touching Skype or having any active voice or chat sessions open, my computer has had 
> communication with 14 IP addresses.  Here is a sample of some:

For "IT administrators" (which probably qualifies most people on this
list) there is a detailed 26 page guide to how Skype communicates on a
network, when you may become a supernode, and how to configure the
program (including to never become a supernode) using GPO (registry
switches) or XML files at
http://download.skype.com/share/business/guides/skype-it-administrators-guide.pdf.

There is a summary of the Supernodes section (concentrating on how to
stop supernodes happening if you have no control of the client) at
http://www.skype.com/intl/en-us/security/universities/.

Anybody who might end up with Skyoe clients on their network might
want to give it a gander, as it has some useful info on things like
network impact (along with a lot of stuff that nobody cares about and
you can skip).

HTH,

Alex