On Fri, Oct 14, 2011 at 12:11 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:
TiggerAir-i7-2:~ patrick$ host 94.193.99.152 152.99.193.94.in-addr.arpa domain name pointer 94-193-99-152.zone7.bethere.co.uk. TiggerAir-i7-2:~ patrick$ host 78.90.137.244 Host 244.137.90.78.in-addr.arpa. not found: 3(NXDOMAIN) TiggerAir-i7-2:~ patrick$ host 175.129.63.150 150.63.129.175.in-addr.arpa domain name pointer KD175129063150.ppp-bb.dion.ne.jp. TiggerAir-i7-2:~ patrick$ host 218.190.29.244 Host 244.29.190.218.in-addr.arpa. not found: 3(NXDOMAIN) TiggerAir-i7-2:~ patrick$ host 128.2.238.215 215.238.2.128.in-addr.arpa domain name pointer ETC-NALZAYER.ETC.CMU.EDU. TiggerAir-i7-2:~ patrick$ host 212.187.172.66 Host 66.172.187.212.in-addr.arpa. not found: 3(NXDOMAIN)
Those do not look like Skype servers. I guess it is possible everyone in my contact list is somehow pinging me, but that seems a little bit silly.
My IP address is 172.30.19.19, hopefully I do not have to explain that this is not a "public IP address". I have been online a few minutes, so unless their uptime requirements are about the same as a regular phone call, it is too short. I will admit, I have plenty of bandwidth available, though.
And, then there is the increasing prevalence of squat space which may muddy common heuristics.
In short, while they can claim my laptop is not being used as a supernode or relay, Skype is still randomly talking to a slew of IP addresses. Anyone know what Skype is doing?
Does Skype on $HANDHELD have the same property? Not as far as I know, for the obvious reason that handheld devices have network connections that are suboptimal for this.
The above happens to my laptop when I am on 3G / EDGE, even when I have a 10-net address. In fact, one of the first things I do on 3G is kill Skype because it noticeably increases my network performance.
I haven't checked on my iPhone 'cause I don't have things like tcpdump & little snitch.
-- TTFN, patrick