Which file should the BIG-IP Administrator check to determine when a Virtual Server changed its status?

/var/log/audit typically logs administrative actions, user logins, and configuration changes, but not the operational status changes of virtual servers themselves.

/var/log/lastlog contains information about the last login time for each user and is not relevant to virtual server status changes.

The /var/log/ltm file, also known as /var/log/tm in older or shorthand references, records events related to the Local Traffic Manager, including status changes for virtual servers, pools, and pool members. This log provides detailed operational messages about the BIG-IP system's traffic processing components.

While monitors influence virtual server status, /var/log/monitors is not a standard log file location on BIG-IP; monitor-related events would typically be found in /var/log/ltm.