Config proxy alcasar

Hi, i am in charge of E-Learning trainings for a great institution. I have installed an instance of jitsi which work perfectly.

My clients are connected behind a proxy Alcasar.

When the connexion is etablished on a PC of my entreprise, the is no video and no sound with my instance but when the connexion is established with, it works. I think this is just severals port to open.

Can you tell me if is running with the defaults ports (10000-udp, 4443-TCP) or if others ports are configured.

Thanks in advance