What ports should be open to allow remote network agent to communicate with main installation?
Q: What ports should be open to allow IPHost main installation to communicate with agents?
A:: Remote Network Agent can operate in two modes: active and passive. In active mode it connects to main installation itself and therefore port should be opened in local network (by default, port 3459 is used; it can be changed in settings). In passive mode agent listens for connections from the main installation, so port should be opened on remote network agent side (port 3457 is used by default, it can be changed in settings via Agent GUI): Distributed Monitoring with Remote Network Agents.
You only need to open a single port in either mode.