Slashdot Mirror
Cheap Point-To-Point VoIP Through NAT?
An anonymous reader asks: "70% of my phone bill comes from calls to a few colleagues. We all have 'broadband' internet access (at least 100 kbit/s upstream) and are behind NATs, so we can share our access with the rest of our house-mates. The OS most used is Linux. In order to lower our phone bills I'm looking for a Point-to-Point audio tool which enables you to pass relatively easily through the NATs. I've had a look at Speak-Freely, which is quite nice as it sports things like GPG-encryption. But it uses two UDP and one TCP ports which is a bit much and not very NAT friendly. I wouldn't like to use commercial tools with central servers like Skype. What would be ok is to use a webserver to serve as a kind of starting point where you would update your IP address and ports. But it should be possible to give your mom and pop webhoster to set up or even better just a cgi-script which interacts with the clients via http or https. The audio data itself shouldn't be routed over a server (what a waste of bandwidth). Thanks for all ideas."
Skype is not centralized. The authentication server is, but the voice traffic is all peer-to-peer.
Skype is nat friendly. All you need to do is forward one port. If you don't, the traffic will still get through by routing through people who are NOT on a nat, encrypted end to end.
I would say that Skype is the most NAT friendly of any of the consumer voice over ip programs, and the voice quality is superior.
Go with Skype; you won't regret it.
SIP based VoIP, Asterisk compatible if you want to get fancy, uses STUN to traverse nat'ing firewalls. They even sponsor a few SIP clients so it's all free, and you can buy a cheap hardware SIP phone or interface and make the calls from a real phone instead of a PC.
Maybe something like http://chownat.lucidx.com/ could be integrated into other software.