Avamar VM Proxy ports

Hi. I had a task to deploy Avamar VM proxy in a very restricted environment, where firewalls exist between VMs, appliances and backup systems. So I checked Avamar VMware PDF guide, and requested to open all the ports listed there. Once they were opened, I tried registering the new proxy, and it failed, returning an error, that it could not communicate to Avamar server on port 28001 🤦 This port was not listed in Avamar VMware guide, it was mentioned only briefly in general Avamar security document.

Currently I have opened the following ports:

Before proceeding with additional request for port 28001, I would like to know if there are any other "secret" ports. My firewall modification process takes a few weeks, so each additional change delays the deployment.