Each Syslog message includes a priority value at the beginning of the text. The priority value ranges from 0 to 191 and is made up of a Facility value and a Level value. The priority is enclosed in "<>" delimiters.
A BSD Unix Syslog message looks like this:
<PRI>HEADER MESSAGE
The priority is a value from 0 to 191 and is not space or leading zero padded.
For more information on the Syslog message format, please read the RFC.
The priority value is calculated using the following formula:
Priority = Facility * 8 + Level
To manually set a particular priority number, enter a number into the Priority value field and check the 'Use this value' box. This value will be sent in the <PRI> field of the Syslog message. This allows you to use values above 191 (up to 255). Values above 191 are illegal and could cause unknown results.