Understanding the network.pdf - Back to Home

use debug mode often. When using the default logging settings, all
the debug messages are sent to the console. This makes using the
console to enter commands difficult, particularly if there is a lot of
debug message feedback. To avoid this, set the console's logging
level to informational; this way, debug messages are set to the
system monitor and the console is clear:
local-AS#config t
Enter configuration commands, one per line. End with CNTL/Z
local-AS(config)#logging console informational
local-AS(config)#^Z
local-AS#
Another case where this is helpful is with the buffer logging method.
Sending debug messages to the buffer will overwrite it rather quickly.
If you plan to use buffered logging at all effectively, set its level at
most to informational. Some care should be taken when using logging
on routers with heavy processing load. Logging, like all router
functions, uses memory and processor resources that can be used for
processing datagrams. If these resources are tight, logging and other
nonessential services will affect router performance.
Setting Up Trap Logging
Sending router messages to a remote host running syslog is more
useful than local logging methods, but it requires a little more work. In
addition to configuring the router, you must set up a host to process
the syslog messages. Syslog comes with most standard UNIX
implementations and is available as an add-on service for Windows NT.
Some resources for NT syslog are the following:
http://www.kiwi-enterprises.com/
http://www.adiscon.com/NTSLog/main.asp
http://www.cls.de/syslog/eindex.htm
Here is an IOS trap logging configuration example: