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/var/log/auth.log or /var/log/secure - Stores authentication logs, including both successful and failed logins and authentication methods. Debian/Ubuntu information is stored in /var/log/auth.log, while Redhat/CentrOS is stored in /var/log/secure.
4. Application Logs: (examples):
/var/log/apache2/ - Apache HTTP server logs (access, error).
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/var/log/yum.log - Red Hat-based systems store the yum and dnf package manager logs, file provides information about the results of a specific command, such as any errors or warnings that were generated. For example, if a package update fails
6. Event Logs:
var/log/wtmp - Records of user logins and logouts.
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