Kosy hosts most services on the following domains:
All of the communication is done using HTTPS or Secure Web Sockets over SSL on port 443.
As Kosy supplies several advanced services, full domain whitelisting may be interesting, as new ports may be required for new features in the future and there is no real security threat to this
Media Server Whitelisting.
Our media servers use static IP addresses rather than DNS-based queries. Kosy uses TCP as well as UDP. It is highly recommended to also allow UDP for media transport performance reasons.
We suggest opening of TCP 443, TCP and UDP port range 50.000 - 65.535 for the servers on our static IP list. If this is not feasible for security reasons (although it should not be an issue generally), a smaller or different range can be opened. If not enough ports are open, voice/video calls may be slowed down as data will have to travel through Kosy servers instead of peer-to-peer.
Our IP list: