Firewall Settings for Auto Provisioning

[ChristophWHAT]

Hello,

I have a question regarding the Yealink Redirection Server.

We are using Yealink T46G / T46P phones.

We have very strict firewall settings, and the autoprovisioning for Yealink isn't working.

If I use the mass deployment link (from VoIP provider) and autoprovision manually it works and the phones connect to tftp and pull the firmware+config files.

I couldn't find the address of the redirection server from Yealink in all the manuals.
What is the port and IP adress that the Yealink phone connects on startup? Is there a firewall configuration manual for Yealink?

Best regards,
Christoph