System Administration Guide: Advanced Administration

Customizing System Message Logging

You can capture additional error messages that are generated by various system processes by modifying the /etc/syslog.conf file. By default, the /etc/syslog.conf file directs many system process messages to the /var/adm/messages files. Crash and boot messages are stored here as well. To view /var/adm messages, see How to View System Messages.

The /etc/syslog.conf file has two columns separated by tabs:

facility.level ... action

A facility or system source of the message or condition. May be a comma-separated listed of facilities. Facility values are listed in Table 15–1. A level, indicates the severity or priority of the condition being logged. Priority levels are listed in Table 15–2.

Do not put two entries for the same facility on the same line, if the entries are for different priorities. Putting a priority in the syslog file indicates that all messages of that all messages of that priority or higher are logged, with the last message taking precedence. For a given facility and level, syslogd matches all messages for that level and all higher levels.


The action field indicates where the messages are forwarded.

The following example shows sample lines from a default /etc/syslog.conf file.

user.err                                        /dev/sysmsg
user.err                                        /var/adm/messages
user.alert                                      `root, operator'
user.emerg                                      *

This means the following user messages are automatically logged:

Note –

Placing entries on separate lines might cause messages to be logged out of order if a log target is specified more than once in the /etc/syslog.conf file. Note that you can specify multiple selectors in a single line entry, each separated by a semi-colon.

The most common error condition sources are shown in the following table. The most common priorities are shown in Table 15–2 in order of severity.

Table 15–1 Source Facilities for syslog.conf Messages




The kernel 




All daemons 


Mail system 


Spooling system 


User processes 

Note –

The number of syslog facilities that can be activated in the /etc/syslog.conf file is unlimited.

Table 15–2 Priority Levels for syslog.conf Messages




System emergencies 


Errors requiring immediate correction 


Critical errors 


Other errors 


Informational messages 


Output used for debugging 


This setting doesn't log output  

ProcedureHow to Customize System Message Logging

  1. Become superuser or assume an equivalent role.

    Roles contain authorizations and privileged commands. For more information about roles, see Configuring RBAC (Task Map) in System Administration Guide: Security Services.

  2. Edit the /etc/syslog.conf file, adding or changing message sources, priorities, and message locations according to the syntax described in syslog.conf(4).

  3. Exit the file, saving the changes.

Example 15–2 Customizing System Message Logging

This sample /etc/syslog.conf user.emerg facility sends user emergency messages to root and individual users.

user.emerg                                      `root, *'