DPMA firewall requirements?

Hello. I have installed a cloud based freepbx server, with DPMA onboard and Digium phones. Everything works fine, apart for the firmware update function. I can download the most up-to-date from Digium no problem, but when I force the phone to download it from my server,it fails.
Now, I have hardened my firewall on the server, so I was wondering if there is any port requirement other than the standard sip/freepbx set that I should add…


Sorry, I realize that what was obvious for me has to be specified in a forum.

I am running the 2.11 freepbx with all modules up-to-date and latest version of Asterisk, installed over a Ubuntu 12.04 server, with a UFW running to allow only minimum required incoming ports, as per documentation. (plus SSH on a custom port obviously).

This is not an installation issue,everything else has been tested and works fine, and the issue is just related to this specific funtion on DPMA. (registration and provisioning working fine)
I have browsed both forum and specific documentation before posting, but I can’t find anything specific to this issue.