The HCL BigFix architecture uses a lightweight notification mechanism to inform clients when new content (such as Fixlets, tasks, or actions) is available. The BigFix Server or Relay sends a small User Datagram Protocol (UDP) packet to the client on its listening port, which is port 52311 by default. This UDP "ping" serves as a notification, prompting the client to wake up and initiate a "gather" process to retrieve the new policy or content information from its parent relay or server. This method is highly efficient for near real-time client management across large networks.

A. TCP: TCP is used for reliable, connection-oriented communication, such as when the client uploads reports or downloads the actual action/Fixlet content, but not for the initial notification ping.

C. ICMP: ICMP is a network layer protocol used for diagnostic purposes and error reporting (e.g., the ping command), not for application-level content notifications.

D. ISMTP: This is a protocol related to email transport and is not used within the HCL BigFix communication architecture.

1. HCL BigFix Platform 10.0 Documentation

Installation Guide

"Port requirements": This official document explicitly states

"UDP port 52311: The BigFix clients listen on this port for notifications from their parent relay that new content is available."

2. HCL BigFix Platform 10.0 Documentation

Overview

"Overview of the architecture": This section describes the communication flow: "When new content is available

the server notifies the relays

which in turn notify the clients. This notification is a small UDP packet that tells the client that a new version of the content is ready for it to gather."

3. HCL BigFix Platform 10.0 Documentation

Capacity Planning

Performance

and Management Guide

"Firewall Configuration": In the table detailing port usage

it lists UDP Port 52311 with the description "Client: Listening for component notifications."