ZyXEL Communications EX3510-B1, User Manual

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EX3510-B1 User’s Guide
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C
HAPTER
21
Log
21.1 Log Overview
These screens allow you to determine the categories of events that the Zyxel Device logs and then
display these logs or have the Zyxel Device send them to an administrator (through e-mail) or to a syslog
server.
21.1.1 What You Can Do in this Chapter
• Use the System Log screen to see the system logs ( Section 21.2 on page 227 ).
• Use the Security Log screen to see the security-related logs for the categories that you select ( Section
21.3 on page 228 ).
21.1.2 What You Need To Know
The following terms and concepts may help as you read this chapter.
Alerts and Logs
An alert is a type of log that warrants more serious attention. They include system errors, attacks (access
control) and attempted access to blocked web sites. Some categories such as
System Errors consist of
both logs and alerts. You may differentiate them by their color in the View Log screen. Alerts display in
red and logs display in black.
Syslog Overview
The syslog protocol allows devices to send event notification messages across an IP network to syslog
servers that collect the event messages. A syslog-enabled device can generate a syslog message and
send it to a syslog server.
Syslog is defined in RFC 3164. The RFC defines the packet format, content and system log related
information of syslog messages. Each syslog message has a facility and severity level. The syslog facility
identifies a file in the syslog server. Refer to the documentation of your syslog program for details. The
following table describes the syslog severity levels.
Table 97 Syslog Severity Levels
CODE SEVERITY
0 Emergency: The system is unusable.
1 Alert: Action must be taken immediately.
2 Critical: The system condition is critical.
3 Error: There is an error condition on the system.
4 Warning: There is a warning condition on the system.