| 5.3 |  | Monitoring with Logging and Syslog |
| 5.3.3 |  | Configuring synchronization of logging messages |

| Administrators can configure the system to synchronize unsolicited messages and debug command output with solicited device output and prompts for a specific line. Types of messages to output can be identified based on the level of severity. Administrators can also determine the maximum number of buffers for storing asynchronous messages for the terminal. Messages that arrive when the number of buffers is exceeded are dropped.

When synchronous logging of unsolicited messages and

debug command output is turned on, unsolicited device output is displayed on the console or printed after the solicited device output is displayed or printed. Unsolicited messages and debug command output is displayed on the console after the prompt for user input is returned. Therefore, unsolicited messages and debug command output are not interspersed with solicited device output and prompts. After the unsolicited messages are displayed, the console displays the user prompt again.

To configure for synchronous logging of unsolicited messages and

debug command output with solicited device output and prompts, use the commands shown in Figure .
Logging is critical to router security. Good logs can help the administrator find configuration errors, understand past intrusions, troubleshoot service disruptions, and react to probes and scans of the network. Cisco routers have the ability to log a great deal of their status. This section explains the different logging facilities, describes the logging configuration commands, and presents some configuration examples.
Enabling time-stamps on log messages
Keeping the correct time on a router is also important for accurate logs. Cisco routers fully support the standard Network Time Protocol (NTP), which is used on the Internet and on all major Department of Defense (DoD) networks to distribute accurate time.

Log messages are not time stamped by default. To enable time stamping of log messages, use either of the commands in Figure while in global configuration mode.