Cisco Catalyst 2000 Configuration Handbook page 218

(Optional) Log messages to terminal sessions.
5.
a. (Optional) Log messages to the switch console:
(global) logging console level
By default, system messages are logged to the console. You can disable logging
with the disable keyword. On an IOS switch, only messages with a severity level
less than or equal to level (0 to 7 or a name from Table 12-1, default 7 or
debugging) are sent to the console.
b. (Optional) Log messages to a Telnet or line session:
(global) logging monitor level
By default system messages are logged to all Telnet and terminal line sessions.
Only messages with a severity level less than or equal to level (0 to 7 or a name
from Table 12-1, default 7 or debugging) are sent to the session.
Note To view system messages during a Telnet or SSH session to a vty line on a switch,
you must issue the terminal monitor EXEC command.
c. (Optional) Control the output of messages to terminal sessions:
(line) logging synchronous [level level | all] [limit buffers]
When synchronous logging is enabled, logging messages are queued until solicit-
ed output (regular output from show or configuration commands, for example) is
displayed. When a command prompt is displayed, logging output will be dis-
played. Synchronization can be used on messages at or below a specific severity
level (0 to 7 or a name from Table 12-1; default 2) or all levels. With the limit
keyword, the switch can queue up to buffer (default 20) messages before they
are dropped from the queue.
Tip Although synchronous logging keeps switch messages from interfering with your typ-
ing or reading other displayed text, it can also be confusing. When synchronous logging is
enabled on the switch console line and no one is currently logged in to the switch, for exam-
ple, the switch queues all messages until the next person logs in. That person sees a flurry
of messages scroll by, possibly from hours or days before.
(Optional) Record a timestamp with each system message:
6.
(global) service timestamps log {uptime | datetime}
By default, a switch records the system uptime. To use the date and time, use the
datetime keyword. This can prove useful if you need to reference an error condition
to the actual time that it occurred.
Tip You should configure and set the correct time, date, and time zone on the switch
before relying on the message logging timestamps. Refer to section "3-8: Time and
Calendar" in Chapter 3, "Supervisor Engine Configuration," for further information.
Chapter 12: Switch Management 197