Powerful threat prediction, prevention, detection, and response along with compliance in a scalable, simple managed solution.
All-in-one networking solution that combines network connectivity, agility, security, and compliance in an affordable managed solution.
Accelerate business growth through our award-winning partner program.
2 min read
If you manage any Linux machines, it is essential that you know where the log files are located, and what is contained in them. Such files are usually in /var/log. Logging is controlled by the associated .conf file.
Some log files are distribution specific and this directory can also contain applications such as samba, apache, lighttpd, mail etc.
From a security perspective, here are 5 groups of files which are essential. Many other files are generated and will be important for system administration and troubleshooting.
1. The main log file
a) /var/log/messages – Contains global system messages, including the messages that are logged during system startup. There are several things that are logged in /var/log/messages including mail, cron, daemon, kern, auth, etc.
2. Access and authentication
a) /var/log/auth.log – Contains system authorization information, including user logins and authentication machinsm that were used.
b) /var/log/lastlog – Displays the recent login information for all the users. This is not an ascii file. You should use lastlog command to view the content of this file.
c) /var/log/btmp – This file contains information about failed login attemps. Use the last command to view the btmp file. For example, “last -f /var/log/btmp | more”
d) /var/log/wtmp or /var/log/utmp – Contains login records. Using wtmp you can find out who is logged into the system. who command uses this file to display the information.
e) /var/log/faillog – Contains user failed login attemps. Use faillog command to display the content of this file.
f) /var/log/secure – Contains information related to authentication and authorization privileges. For example, sshd logs all the messages here, including unsuccessful login.
3. Package install/uninstall
a) /var/log/dpkg.log – Contains information that are logged when a package is installed or removed using dpkg command
b) /var/log/yum.log – Contains information that are logged when a package is installed using yum
a) /var/log/daemon.log – Contains information logged by the various background daemons that runs on the system
b) /var/log/cups – All printer and printing related log messages
c) /var/log/cron – Whenever cron daemon (or anacron) starts a cron job, it logs the information about the cron job in this file
b) /var/log/maillog /var/log/mail.log – Contains the log information from the mail server that is running on the system. For example, sendmail logs information about all the sent items to this file
b) /var/log/Xorg.x.log – Log messages from the XWindows system
Download Whitepaper Now!
Netsurion’s managed platform approach offers you unmatched flexibility and scalability. Use our Solution Advisor Wizard to customize a solution to best fit your needs.
Solution Advisor Wizard
10 min read
5 min read