syslog

What is syslog?

Syslog is a standard protocol used for logging system events across networked devices. It is commonly used to collect, store, and analyze logs from different devices like servers, routers, firewalls, and switches. Syslog simplifies troubleshooting, security monitoring, and compliance auditing by centralizing logs into a single location.

Key Components of Syslog

1. Syslog server: centralized location where logs are collected and stored.

2. Syslog client: Device or application that sends log messages to the server.

3. Log levels: Define the severity of log messages. Common levels include:

   • 0: Emergency

   • 1: Alert

   • 2: Critical

   • 3: Error

   • 4: Warning

   • 5: Notice

   • 6: Informational

   • 7: Debug

4. Facilities: Indicate the type of system that generated the message (e.g., kernel, mail, authentication).

Commands

Name	Description
yum install syslog	install syslog
tail -f /var/log/syslog	view syslog files
grep "error" /var/log/syslog	search for specific logs
awk '/Jan 23/ {print}' /var/log/syslog	filter logs by date
logger -p local0.info "This is a test syslog message"	send a test message