Explanation:
Microsoft Exchange - Server monitoring
Linux authentication - syslog monitoring
Windows Client - client probing
Citrix client - Terminal Services agent

Explanation
Reconnaissance - stage where the attacker scans for network vulnerabilities and services that can be exploited.
Installation - stage where the attacker will explore methods such as a root kit to establish persistence Command and Control - stage where the attacker has access to a specific server so they can communicate and pass data to and from infected devices within a network.
Act on the Objective - stage where an attacker has motivation for attacking a network to deface web property