
The April IANA port-numbers list now show that UDP and TCP port 4166 belong to Joost.
As of beta 0.9.2 those ports are not currently used by Joost. It is highly likely that Joost will stop using “unregistered” TCP port 5223 and UDP port 33333 in favor of the IANA ones to transport it’s traffic.
Port mapping will most likely go as:
- UDP 33333 -> UDP 4166
- TCP 5223 -> TCP 4166
In it’s current form the beta 0.9.2 client requires the following port to run:
- TCP access, outbound, to ports 80, 443 and 5223.
- UDP access, outbound, to port 33333.
- If you have a public IP address and UDP inbound on port 33333 is unfiltered, the client may use UDP on port 33333 inbound.
- If you want to chat from within Joost, you’ll also need to enable inbound TCP access to port 5223.
Update:
Just found out that Colm MacCarthaig is the registered owner. Colm is an employee of Joost.

[...] 4166: la IANA ha assegnato ufficialmente la porta 4166 sui protocolli UDP e TCP a Joost. [fonte] [...]