Filter functions

This section describes filter functions in syslog-ng OSE.

The following functions may be used in the filter statement, as described in Filters.

Table 14: Filter functions available in syslog-ng OSE

Name	Description
facility()	Filter messages based on the sending facility.
filter()	Call another filter function.
host()	Filter messages based on the sending host.
in-list()	File-based whitelisting and blacklisting.
level() or priority()	Filter messages based on their priority.
match()	Use a regular expression to filter messages based on a specified header or content field.
message()	Use a regular expression to filter messages based on their content.
netmask() or netmask6()	Filter messages based on the IP address of the sending host.
program()	Filter messages based on the sending application.
rate-limit()	Limits messages rate based on arbitrary keys in each message.
source()	Select messages of the specified syslog-ng OSE source statement.
tags()	Select messages having the specified tag.
blank()	Filter messages where the specified value is blank (unset, empty, whitespace-only, empty list, or boolean false).