This article describes how Server Agent determines the hostname that is then displayed in Registered Clients list in Aperture.
The Server Agent will report back to Venafi Trust Protection Platform (TPP) the hostname of the system. This hostname value is determined by a system call made by the Agent.
The call is gethostname (https://man7.org/linux/man-pages/man2/gethostname.2.html). This function is used by hostname command at least in Linux (https://man7.org/linux/man-pages/man1/hostname.1.html).
This means that on a Linux system we can simply run this command from terminal session to see what the Agent should be reporting as the hostname:
On Windows you can use the following PowerShell command: