Ports for IIS management

I have some VBScripts that backup IIS configurations and save the
configurations to a centralized repository. Two of my servers are in a DMZ
and the server that automatically executes these scripts is on our internal
LAN. Below are a couple of examples of the objects that I am creating and the
paths that are being utilized.

Set IISObject = GetObject("IIS://servername")

Set IISObject = GetObject("IIS://servername/W3SVC")

My question is, If we go through the firewall to connect to this server,
what port(s) needs to be opened?