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
facility.level
A facility
or system source of the message
or condition. May be a comma-separated listed of facilities. Facility values are listed
in Table 22–1. A level
,
indicates the severity or priority of the condition being logged. Priority levels
are listed in Table 22–2.
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.
action
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:
User errors are printed to the console and also are logged to the
/var/adm/messages
file.
User messages requiring immediate action (alert
)
are sent to the root and operator users.
User emergency messages are sent to individual users.
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 22–2 in order of severity.
Table 22.1. Source Facilities for syslog.conf
Messages
Source |
Description |
---|---|
|
The kernel |
|
Authentication |
|
All daemons |
|
Mail system |
|
Spooling system |
|
User processes |
The number of syslog
facilities that can be activated
in the /etc/syslog.conf
file is unlimited.
Table 22.2. Priority Levels for syslog.conf
Messages
Priority |
Description |
---|---|
|
System emergencies |
|
Errors requiring immediate correction |
|
Critical errors |
|
Other errors |
|
Informational messages |
|
Output used for debugging |
|
This setting doesn't log output |
How to Customize System Message Logging
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 .
Edit the /etc/syslog.conf
file, adding
or changing message sources, priorities, and message locations according to the syntax
described in
syslog.conf
(
4
)
.
Exit the file, saving the changes.