Logging of messages
to an SNMP NMS is enabled by the
traps command. Because SNMP traps are inherently unreliable and
much too important to lose, at least one syslog message, the most recent
message, is stored in a history table on the router.
history command to reflect the history of last 500 syslog
messages. For example, when this command is issued, the last 500 syslog
messages with severity less than warning message are displayed in the output of
show logging history
command to display the history table, which contains table
size, message status, and message text data.
logging history size command to change the number of
messages stored in the history table.
The value specified
argument causes messages at that severity level and at numerically lower levels
to be stored in the history table of the router and sent to the SNMP NMS.
Severity levels are numbered 0 to 7, with 1 being the most important message
and 7 being the least important message (that is, the lower the number, the
more critical the message). For example, specifying the level critical with the
keyword causes messages at the severity level of
alerts (1), and
to be stored in the history table and sent to the SNMP NMS.
history command resets the history level to the