The following topics list the standard fields of each
log type that Palo Alto Networks firewalls can forward to an external
server, as well as the severity levels, custom formats, and escape
sequences. To facilitate parsing, the delimiter is a comma: each field
is a comma-separated value (CSV) string. The FUTURE_USE tag applies
to fields that the firewalls do not currently implement.
WildFire Submissions logs are a subtype of Threat log and
use the same syslog format.