How to check firewall log messages

Reviewing firewall logs

At times, it may be necessary to review firewall log data to troubleshoot blocked connections or applications. There are multiple ways to view this information.

Graphical User Interface

From the Gnome menu, select System, Administration, Log File Viewer. You may also launch the Log Viewer tool with the command /usr/bin/system-logviewer. Be sure to select the file messages from the left hand portion of the window:

Command Line Interface

Linux systems use syslog to capture iptables log data. By default, these entries are stored in /var/log/messages. This file can be reviewed, searched, or viewed in real time.

View the logs in real time

Open a terminal window, and use the following command:

sudo tail -f /var/log/messages |grep FIREWALL

If you need to view the kernel buffer diagnostic messages, some of which are network related, run the command dmesg from a terminal window.