Redirecting Debug And Error Message Output - Cisco Catalyst 2975 Software Configuration Manual

Chapter 38 Troubleshooting
Because debugging output takes priority over other network traffic, and because the debug all privileged
Caution
EXEC command generates more output than any other debug command, it can severely diminish switch
performance or even render it unusable. In virtually all cases, it is best to use more specific debug
commands.
The no debug all privileged EXEC command disables all diagnostic output. Using the no debug all
command is a convenient way to ensure that you have not accidentally left any debug commands
enabled.

Redirecting Debug and Error Message Output

By default, the network server sends the output from debug commands and system error messages to the
console. If you use this default, you can use a virtual terminal connection to monitor debug output
instead of connecting to the console port.
Possible destinations include the console, virtual terminals, internal buffer, and UNIX hosts running a
syslog server. The syslog format is compatible with 4.3 Berkeley Standard Distribution (BSD) UNIX
and its derivatives.
Be aware that the debugging destination you use affects system overhead. Logging messages to the
Note
console produces very high overhead, whereas logging messages to a virtual terminal produces less
overhead. Logging messages to a syslog server produces even less, and logging to an internal buffer
produces the least overhead of any method.
When stack members generate a system error message, the stack master displays the error message to
all stack members. The syslog resides on the stack master.
Note Make sure to save the syslog to flash memory so that the syslog is not lost if the stack master fails.
For more information about system message logging, see
Logging."
Using the show platform forward Command
The output from the show platform forward privileged EXEC command provides some useful
information about the forwarding results if a packet entering an interface is sent through the system.
Depending upon the parameters entered about the packet, the output provides lookup table results and
port maps used to calculate forwarding destinations, bitmaps, and egress information.
For more syntax and usage information for the show platform forward command, see the switch
Note
command reference for this release.
Most of the information in the output from the command is useful mainly for technical support
personnel, who have access to detailed information about the switch application-specific integrated
circuits (ASICs). However, packet forwarding information can also be helpful in troubleshooting.
OL-19720-02
Using the show platform forward Command
Chapter 29, "Configuring System Message
Catalyst 2975 Switch Software Configuration Guide
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