Agent Call Home

Purpose

This document describes the agents Call Home function.

Introduction

An Outpost24 agent performs a call home regularly to send and receive data from the agent server. The agent Call Home frequency depends on the amount of agents that is deployed. When setting up an agent for the first time, the agent Call Home frequency is set to one hour. When setting up large amounts of agents that all call within the one hour period there is a risk that several agents are going to call home simultaneously resulting agents calling home every second in average to a single agent server thus overloading it. It is therefore necessary to reassess the Call Home frequency in environment with many agents.

Call Home Workflow

A call home contains several actions executed in sequence:

Enroll - The agent sends its identity to the Agent Server and receive a certificate back after a successful enrollment.
Apply Agent Configuration - The agent retrieves its configuration from the Agent Server and saves it.
Update Agent Data - The agent sends information about itself to the Agent Server.
Upload Scan Data - Send module result for each schedule to the Agent Server and deletes them locally after a successful upload.
Update Schedule - Request the list of schedules that have been sent to the Agent Server and store them locally.

Call Home Frequency

The Call Home frequency is calculated once an agent performs an successful enrollment and is based on the amount of active agents that the same customer owns and follow a linear pattern.

The frequency is reassessed every time a successful agent enrollment has been performed, and as the number of active agents increase the call home frequency increases in a linear pattern and is updated for all active agents.

Retired agents are not relevant and is not taken into account when calculating the new call home frequency.

State	Call Home Frequency
Default	Based on number active agents and follows a linear pattern.
Unscheduled	High
Retired	Very Low

Default Call Home Frequency

The default Call Home frequency is calculated based on the number of active agents.

Retired Agents

In Main Menu > NetSec > Manage Targets retired agents are visible in the Agent Retired column, and are given a prolonged window with a very low frequency to call home and have its scans disabled.

Unscheduled Agents

If an agent is active but unscheduled, then the call home frequency is maintained at higher level to retrieve its schedule.

Customizing the Call Home Frequency Linear Function on DS Agents

DS Agent servers have the ability to customize the Call Home frequency linear function.

To customize the Call Home frequency linear function add the following in the agent server setting file.

callHome:
  agentLow: 1000
  agentHigh: 20000
  frequencyLow: 60
  frequencyHigh: 280

Parameter	Description
agentLow	Numbers of active agents
agentHigh	Numbers of active agents
frequencyLow	Duration in minutes
frequencyHigh	Duration in minutes

All four parameters must have values to customize the linear function.

Leaving the values empty will cause the Call Home function to fail.

Do not add the callHome: section to the setting file unless you want to customize it.