1. /var/log/message: General message and system related stuff.
2. /var/log/maillog: Mail server logs.
3. /var/log/auth.log: Authenication logs.
4. /var/log/kern.log: Kernel logs.
5. /var/log/cron.log: Crond logs (cron job).
6. /var/log/qmail/ : Qmail log directory (more files inside this directory).
7. /var/log/httpd/: Apache access and error logs directory.
8. /var/log/lighttpd: Lighttpd access and error logs directory.
9. /var/log/boot.log : System boot log.
10. /var/log/mysqld.log: MySQL database server log file
11. /var/log/secure: Authentication log.
12./var/log/utmp or /var/log/wtmp : Login records file
13. /var/log/yum.log: Yum log files
god bless you