APP-NAME field of the Syslog message as defined in RFC 5424 - The syslog Protocol.

The APP-NAME field SHOULD identify the device or application that originated the message. It is a string without further semantics. It is intended for filtering messages on a relay or collector.

The NILVALUE MAY be used when the syslog application has no idea of its APP-NAME or cannot provide that information. It may be that a device is unable to provide that information either because of a local policy decision, or because the information is not available, or not applicable, on the device.

This field MAY be operator-assigned.