Rich's Tongfamily (Richtong.net add-on)

a little ludwig goes a long way: NATs and VOIP. I’m amazed. Ludwig found he could just use his VOIP phone from his phone without dinking with his firewall. I wonder how Vonage figured this out?
I bet Gary Burd: NATs and Internet telephony is right that what they are doing is having an intermediary so that Vonage on Ludwig’s machine only has an outbound port and it is not true peer-to-peer when doing PC-to-PC. Since Vonage is really designed for PC-to-PSTN that makes sense. As Gary points out the problem is that you aren’t peer-to-peer so the server side has to pay for hauling the traffic up and down.
That is how AOL IM for instance works today. OK for text, but what happens when people ship 5MB pictures to and fro.