Web interface fails to start. Fix: service acs stop → service database stop → service acs start (yes, in that strange order).
The .iso extension indicates that ACS 4.2 was delivered as a bootable operating system image, not a Windows application. It runs atop a stripped-down version of Red Hat Linux. CISCO ACS 4.2.iso
Before deploying Cisco ACS 4.2, it is vital to understand the risks involved: Web interface fails to start
Cisco Secure Access Control Server (ACS) 4.2 is a legacy authentication, authorization, and accounting (AAA) platform that was commonly used for controlling access to network devices using RADIUS and TACACS+ protocols CISCO ACS 4.2.iso