Troubleshooting Commands
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the time you will see something that wasn't there before, see something that
shouldn't be there, or notice that something is missing that needs to be in the
configuration. For this technique to work, you must be familiar with the
router and its configuration. If backups are made of the configurations, you
may compare them to the running-config to look for differences.
show logging
The logs kept by the router can be very useful because they can be the first indica-
tion of a network problem. The router itself logs errors and details regarding the
error. Seven different levels of warning messages exist. The scale is from one to
seven--one is the lowest priority and seven is a critical warning.
There are six types of logging: syslog, console, monitor, trap, buffer, and
SNMP. Each may be logged to the console, or to a syslog or SNMP server.
Following is the output from the show logging command:
Router_B>show logging
Syslog logging: enabled(0 messages dropped, 202 flushes, 0
overruns)
Console logging: level debugging, 9199 messages logged
Monitor logging: level debugging, 1517 messages logged
Trap logging:level informational,5 message lines
logged
Logging to 172.16.1.1, 2288 message lines logged
Logging to 272.16.2.4, 2288 message lines logged
Buffer logging: level debugging, 5688 messages logged
SNMP logging: enabled, retransmission after 60 seconds
741 messages logged
Logging to 172.16.34.2, 0/10
Log Buffer (16000 bytes):
The output simply tells us that syslog, console, monitor, trap, buffer, and
SNMP are all enabled. If they are not enabled, the output indicates the status.
It gives some statistical information about the number of messages logged and
to where they are logged.
show buffers
The show buffers command was described in detail in the earlier "Buffer
and Queue Architecture in a Cisco 7000" section. Please refer to that section
if you need to review the output of the show buffers command.
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