The syslog-ng 3.0 Administrator Guide

Figure 2.5. Relay-mode operation

In relay mode, syslog-ng receives logs through the network from syslog-ng clients and forwards them to the central syslog-ng server using a network connection. Relays can also log the messages from the relay host into a local file, or forward these messages to the central syslog-ng server.

Relays cannot write messages received from the network into local files, only buffer the messages to the hard disk when disk-based buffering is used.

No license file is required to run syslog-ng in relay mode.