As info about Idc config is missing here I just can speculate what’s going on.
Most likely you’re using AD polling as identity source, not sylog or ISE (pxGrid)
So basically, the reason you’re not seeing the Domain Controller show up is because the Identity Collector relies on security events that are generated when clients authenticate to the domain. When a normal client logs in, a security event is created that ties the user identity to the machine and its IP address. The Identity Collector uses these events to build the user-to-IP and machine mappings.
Domain Controllers themselves do not generate these kinds of user login events for their own identity. They operate as infrastructure components and typically run under system accounts, so there are no relevant security events that Identity Awareness can use to identify the DC as an endpoint. Therefore, this behavior is expected and not a misconfiguration.
As an alternative approach, we are currently in a testing phase using 802.1X together with Cisco ISE. In this setup, session information is shared via pxGrid (Security Group Tags / SGT) which can then be consumed by the Identity Engine / Identity Collector. This approach does work and provides visibility even for servers or infrastructure devices that do not have interactive user logins.
and now to something completely different - CCVS, CCAS, CCTE, CCCS, CCSM elite