KBI 311314 Issue Addressed: Remote Trusted Agent Pointing To Daughter Engine Generates Error Message Invalid Protocol Request


Argent Advanced Technology between 3.1A-1407-A and 3.1A-1510-A


Tuesday, 24 November 2015


When a Trusted Agent is installed with option ‘Use TCP/IP Communication Only For Trusted Agents’ and pointing to Daughter Engine, the Trusted Agent does not functioning properly

Following error messages can be found in service log:

Could not read reply. Error: Invalid protocol request. Please check if services are installed properly

The Trusted Agent installed without option ‘Use TCP/IP Communication Only For Trusted Agents’ works correctly with Daughter Engine

The Trusted Agent pointing to Mother Engine always works with or without the option

The issue has been addressed in Argent AT 3.1A-1510-T9

Technical Background

When a Daughter Engine is overloaded, it might be necessary to deploy Trusted Agents pointing to Daughter Engine

As results, the monitoring tasks assigned to the Daughter Engine can be offloaded to the Trusted Agents

Another typical case is to allow Daughter Engine monitoring DMZ servers at the remote office

The Trusted Agent must be deployed in the DMZ

Sometimes it has to be installed locally for a locked down server

When Trusted Agent is installed pointing to a Daughter Engine, it is the Daughter Engine that drives the Trusted Agent

There is no communication between the Trusted Agent and Mother Engine

A Trusted Agent communicates with Supervising Engine, Daughter Engine in this case, either through file share or TCP/IP

It depends on whether the option ‘Use TCP/IP Communication Only For Trusted Agents’ is checked during setup time

The coding error was found only in the TCP/IP related code

As a result, Trusted Agents installed with the option unchecked, are not affected by the issue


Upgrade to Argent AT 3.1A-1510-T9 or later

For customer who cannot upgrade immediately, install Trusted Agent without option ‘Use TCP/IP Communication Only For Trusted Agents’