A Practical Guide to Logstash: Syslog Deep Dive
Syslog is a popular standard for centralizing and formatting log data generated by network devices. It provides a standardized way of generating and collecting log information, such as program errors, notices, warnings, status messages, and so on. Almost all Unix-like operating systems, such as those based on Linux or BSD kernels, use a Syslog daemon that is responsible for collecting log information and storing it.