Syslog

Description

From https://syslog-ng.org:

syslog-ng allows you to flexibly collect, parse, classify, and correlate logs from across your infrastructure and store or route them to log analysis tools.

Security Onion usage

Security Onion uses syslog-ng as its primary syslog collector and to send logs to ELSA.

Configuration

syslog-ng's configuration file is located at /etc/syslog-ng/syslog-ng.conf

Sending Logs to Other Systems

Syslog-ng can be integrated with third-party systems to forward Bro, OSSEC, or IDS alerts.

More Information

For more information about syslog-ng, please see:
https://syslog-ng.org/

syslog-ng listens on port 514 (TCP and UDP) for incoming syslog from other devices (you may need to run so-allow to allow traffic from the IP address of your syslog sender). This gives you basic log collection. If you'd like those logs collected from other devices to be analyzed, another option is to configure OSSEC to receive syslog directly on a port other than the syslog-ng port of 514:
http://ossec-docs.readthedocs.org/en/latest/syntax/head_ossec_config.remote.html
http://www.ossec.net/ossec-docs/OSSEC-book-ch3.pdf