The Syslog Defined
Before getting into the syslog and what it is, it is first important to understand its relation to the UNIX operating system and subsequent variations on that operating system.

First developed by AT&T in the late 1960's, UNIX source code was later distributed among universities for use and further research and development. From this initial distribution of licenses, different variations of the UNIX operating system were created while the UNIX source code was bought and sold, changing hands a number of times before the brand name itself was obtained and trademarked by The Open Group.

Today, Linux stands as an example of a flavor of a flavor of the initial UNIX OS. While it does resemble UNIX in some ways, it contains none of its original source code.

The syslog (also known as the UNIX System Logger or GNU/Linux System Logger) is the system resource for all messages or errors generated by UNIX based systems.

In addition to any UNIX computers, hardware components such as routers and firewalls even on Windows based networks can generate syslog messages.

Other resources:

Windows Resources for UNIX Professionals
Provided by Microsoft.

IT Toolbox UNIX Knowledge Base