Syslog message priorities
At the beginning of each Syslog message, there is a priority value. The priority value is calculated using the following formula:
Priority = Facility * 8 + Severity
Syslog facilities
The facility value indicates which machine process created the message. The Syslog protocol was originally written on BSD Unix, so Facilities reflect the names of UNIX processes and daemons.
If you are receiving messages from a UNIX system, consider using the User Facility as your first choice. Local0 through Local7 are not used by UNIX and are traditionally used by networking equipment. Cisco routers, for example, use Local6 or Local7.
|
Number |
Source |
Number |
Source |
|---|---|---|---|
|
0 |
kernel messages |
12 |
NTP subsystem |
|
1 |
user-level messages |
13 |
log audit |
|
2 |
mail system |
14 |
log alert |
|
3 |
system daemons |
15 |
clock daemon |
|
4 |
security/authorization messages |
16 |
local use 0 (local0) |
|
5 |
messages generated internally by Syslog |
17 |
local use 1 (local1) |
|
6 |
line printer subsystem |
18 |
local use 2 (local2) |
|
7 |
network news subsystem |
19 |
local use 2 (local3) |
|
8 |
UUCP subsystem |
20 |
local use 2 (local4) |
|
9 |
clock daemon |
21 |
local use 2 (local5) |
|
10 |
security/authorization messages |
22 |
local use 2 (local6) |
|
11 |
FTP daemon |
23 |
local use 2 (local7) |
Syslog severities
The following table provides a list of Syslog severity levels with descriptions and suggested actions for each.
|
Number |
Severity |
Suggested Actions |
|---|---|---|
|
0 |
Emergency |
A "panic" condition affecting multiple applications, servers, or sites. System is unusable. Notify all technical staff on call. |
|
1 |
Alert |
A condition requiring immediate correction, for example, the loss of a backup ISP connection. Notify staff who can fix the problem. |
|
2 |
Critical |
A condition requiring immediate correction or indicating a failure in a primary system, for example, a loss of a primary ISP connection. Fix CRITICAL issues before ALERT-level problems. |
|
3 |
Error |
Non-urgent failures. Notify developers or administrators as errors must be resolved within a given time. |
|
4 |
Warning |
Warning messages are not errors, but they indicate that an error will occur if required action is not taken. An example is a file system that is 85% full. Each item must be resolved within a given time. |
|
5 |
Notice |
Events that are unusual but are not error conditions. These items might be summarized in an email to developers or administrators to spot potential problems. No immediate action is required. |
|
6 |
Informational |
Normal operational messages. These may be harvested for network maintenance functions like reporting and throughput measurement. No action is required. |
|
7 |
Debug |
Information useful to developers for debugging an application. This information is not useful during operations. |