Rsyslog utilizes the standard BSD syslog protocol, as specified in RFC 3164. Since the text of RFC 3164 is an informational description rather than a standard, multiple incompatible extensions have developed. Rsyslog provides support for several of these extensions and facilitates the customization of relayed messages' format.
Rsyslog is an open-source software tool utilized on UNIX and UNIX-like computer systems to forward log messages across an IP network. It implements the basic syslog protocol while extending it with content-based filtering, rich in features. The RSYSLOG utility offers various features including filtering abilities, queue management for handling offline outputs, support for different module outputs, flexible configuration options, and the use of TCP for transport.
According to the official RSYSLOG website, this utility is "the rocket-fast system for log processing".
Rsyslog utilizes the standard BSD syslog protocol, as specified in RFC 3164. Since the text of RFC 3164 is an informational description rather than a standard, multiple incompatible extensions have developed. Rsyslog provides support for several of these extensions and facilitates the customization of relayed messages' format.
(Source: https://en.wikipedia.org/wiki/Rsyslog)
Installation
Depending on the distribution used, install the rsyslog package.
Starting service:
You can start/enable ryslog.service after installation
Configure hostname.
Rsyslog use system call gethostname() or gethostbyname() to determine the hostname of the local machine which take contest of /etc/hosts for FQDN (Fully Qualifed Domain Name). This is the same output as if you call hostname --fqdn command.
Configuration
The configuration for rsyslog is stored in the /etc/rsyslog.conf file. Refer to the official documentation for further information.
Facility level
Despite the possibility for various facility and severity levels within syslog, all messages originating from CLIP are configured to have a facility of 1 (user-level messages) and a severity of 6 (informational).