All log files on linux servers are normally located under /var/log directory.
a) /var/log/message: – This is standard system log file in which various system applications and daemons record their messages.
b) /var/log/auth.log: It has authentication logs
c) /var/log/kern.log: It has kernel logs
d) /var/log/cron.log: It has crond logs.
e) /var/log/maillog: It has mail server logs
f) /var/log/qmail/ : It has qmail log directory
g) /var/log/httpd/: Apache access and error logs directory
h) /var/log/lighttpd: It has Lighttpd access and error logs directory
i) /var/log/boot.log : It has system boot log
j) /var/log/mysqld.log: It has MySQL database server log file
k) /var/log/secure: Authentication log
l) /var/log/utmp or /var/log/wtmp : Login records file
m) /var/log/yum.log: It has Yum log files