The "PRIORITY" parameter is actually a combination of the facility and severity.
From the syslog spec (
http://tools.ietf.org/html/rfc3164#section-4.1.1):
Numerical Facility
Code
0 kernel messages
1 user-level messages
2 mail system
3 system daemons
4 security/authorization messages (note 1)
5 messages generated internally by syslogd
6 line printer subsystem
7 network news subsystem
8 UUCP subsystem
9 clock daemon (note 2)
10 security/authorization messages (note 1)
11 FTP daemon
12 NTP subsystem
13 log audit (note 1)
14 log alert (note 1)
15 clock daemon (note 2)
16 local use 0 (local0)
17 local use 1 (local1)
18 local use 2 (local2)
19 local use 3 (local3)
20 local use 4 (local4)
21 local use 5 (local5)
22 local use 6 (local6)
23 local use 7 (local7)
Numerical Severity
Code
0 Emergency: system is unusable
1 Alert: action must be taken immediately
2 Critical: critical conditions
3 Error: error conditions
4 Warning: warning conditions
5 Notice: normal but significant condition
6 Informational: informational messages
7 Debug: debug-level messages
The Priority value is calculated by first multiplying the Facility
number by 8 and then adding the numerical value of the Severity. For
example, a kernel message (Facility=0) with a Severity of Emergency
(Severity=0) would have a Priority value of 0. Also, a "local use 4"
message (Facility=20) with a Severity of Notice (Severity=5) would
have a Priority value of 165. In the PRI part of a syslog message,
these values would be placed between the angle brackets as <0> and
<165> respectively. The only time a value of "0" will follow the "<"
is for the Priority value of "0". Otherwise, leading "0"s MUST NOT be
used.
