I saw a presentation on ring.cx and thought it sounded good. It has a lot of modern requirements but I may attempt it in a vm. If you have tried it and use it how do you like so far? From their page: "Ring is a secure and distributed voice, video and chat communication platform that requires no centralized server and leaves the power of privacy in the hands of the user."

Ekiga has been around for a while.
But having no use for such a program (whatsoever) I had not followed the development.

Is that the only selling point of it, that it's been around awhile? How does it compare to ring.cx?

They have packages for installing on Debian 8 (stable/jessie), so can't have TOOO modern of requirements given that Jessie still uses a 3.16 kernel by default.

GTK+ >= 3.10
QT5

Don't know of any kernel dependencies.

Setup on Debian is trivial for ring, it has debian stable and testing repos. Don't worry, they dont mess up your system because they contain only their own packages.

It actually uses SIP for audio/video (encrypted). And here is the problem:
Actually using audio/video calls NEEDS upnp if you are behing NAT (unless you are on the same LAN or VPN, you are behind NAT). If you don't have upnp support activated on your router, calls do not connect (i never activate upnp and didnt work for me). This is unfortunate because on many occasions when you use networks that are not under your control you wont have upnp.
When it connects, (worked just fine with both ends connected on my vpn) it does work well.

BTW Skype enabled webrtc audio calls from the web.skype.com web interface (works on Chrome on Linux) and video calls will follow so pretty much all functionality from the soon-to-be-deprecated Linux client can be used there.

I used skype once but the call was clearly intercepted/blocked multiple times and that was the first and last time I used that POS. I think that was before M$ bought it (which removed any thought of ever using it again)

upnp is universal plug-n-play and enabling that (IIRC) allows UDP over certain ports on the firewall/router.

So to make Ring.cx work you:

pc->lan->vpn->wan->vpn->ring.cx_user_with_upnp

or

pc->lan->vpn->wan->vpn->ring.cx_user_with_vpn



I think upnp can be used safely but with the correct set of netfilter firewall rules.

If both users are in the same vpn (and if that vpn permits connection between it's peers), you don't need upnp at all since the network discovery will use direct connections between the vpn ip addresses.

The problem with upnp is that if you are on a network which is not controlled by you there is a chance to have upnp disabled on the router and you will not able to use ring for calls regardless of your upnp settings in ring.

I took a look at ring, and even installed it as it's in Debian's Unstable repositories but I gave up on the idea after reading that it needs UPnP. I'm just not prepared to start opening up random vulnerabilities in my router in the hope that nobody bothers to hack them.

But then you might as well use skype. The whole point of ring.cx is secure peer to peer communication. With a VPN in the middle you have "something" in the middle.

upnp can be made secure with the right firewall rules. I bet that the ring.cx folks provide those either in ring.cx docs or on the forum, etc.

Umm. I was referring to a vpn YOU run on YOUR own computer/server (i have one openvpn instance and it has no noticeable performance impact, especially if you use aes256 because that is hardware accelerated on modern cpus). So ring (or anything really) will use your own infrastructure for actual data transfer (the rest of the comminucation takes place in the DHT).
But in this case really you can set up an xmpp server (very easy) and use jitsi for audio/video so nothing will be outside your control.

I don't use VPNs. You also presume VPNs are secure from pt-to-pt. I think you're missing the point of ring.cx.

Also ring.cx traffic wouldn't need any encryption, it's already encrypted. To me a VPN seems like a lot of extra work to avoid making netfilter rules for UPnP.

You do realize that upnp has to be enabled on the network firewall for the network you are in?

What happens if someone you want to call or you is behind a firewall that has no enabled upnp (e.g most company firewalls) and has no access to the configuration of the firewall? The call fails. And noone (besides the admins of course) can do anything about it.
BTW how is over 3g/4g? AFAIK there is no upnp compatibility.
So for this cases ring is UNUSABLE as audio/video tool. That was my point.

Nothing is to be 100% trustworthy nowadays, but i will trust more a vpn set up and operated by me on my computers (not third party vpns!) than any 3rd party tool that relays/keeps my data who knows where and works in ways i don't fully understand.

There's a technique to get around some of these limitations. Used for games. Don't remember if it's called
UDP bypass or something else. The name doesn't come to mind at the moment.

See above.

That's good. But the problem is that not everyone will have a VPN or even have access to one. So peer-to-peer is becoming the way to go.

I was close, the technique is called UDP hole punching. Skype does this also.