> This is one thing I'm surprised the open source community hasn't developed a popular alternative for: Teamviewer.
That's because it's not only a matter of software but also a matter of service (STUN is not enough, TURN is required in many situations. And someone has to pay for the servers and bandwidth...). If IPv6 had succeded instead of IPv4+NAT, maybe the situation would be different.
In terms of software, the open-source x2go (based on nomachine NX libraries and protocol, see https://wiki.x2go.org/doku.php) has been very efficient in my cases when bandwidth was limited and when I had no big NAT issues.
I enjoy using x2go, but it's not exactly an easy to use system. If either end of the connection needs to change firewall settings or enter IP addresses, it's already far behind on usability. It could work with some setup in corporate environments, but doing this right is quite a pain for smaller businesses.
I agree that STUN/TURN servers are a necessity, but they're not _that_ expensive to self-host. You could stuff the STUN/TURN feature behind rate limits for the hosted version or put them behind a pay wall entirely so companies don't have to mess around with that stuff themselves.
That's because it's not only a matter of software but also a matter of service (STUN is not enough, TURN is required in many situations. And someone has to pay for the servers and bandwidth...). If IPv6 had succeded instead of IPv4+NAT, maybe the situation would be different.
In terms of software, the open-source x2go (based on nomachine NX libraries and protocol, see https://wiki.x2go.org/doku.php) has been very efficient in my cases when bandwidth was limited and when I had no big NAT issues.