122 Con?¬?guring Syslog Logging
Con?¬?guring Syslog Logging
Cisco routers are capable of logging information relating to a number of different kinds of
events that occur on a router??”con?¬?guration changes, ACL violations, interface status, and
so on. Cisco routers can direct these log messages to several different locations: console,
terminal lines, memory buffers, SNMP traps, or an external syslog server.
In order to get the most out of your router log messages, it is imperative that your routers
display the correct time; using NTP will help facilitate your routers all having the correct
time.
There are eight levels of severity in logging messages:
Router(config-line)#transport input ssh Enables SSH on all ?¬?ve
vty lines
NOTE: Cisco routers
with Cisco IOS Release
12.1(3)T and later can
act as SSH clients as
well as SSH servers.
This means that you
could initiate an SSH
client-to-server session
from your router to a
central SSH server
system.
Level Name De?¬?nition Example
0 emergencies System is unusable Cisco IOS Software could not
load
1 alerts Immediate action needed Temperature too high
2 critical Critical conditions Unable to allocate memory
3 errors Error conditions Invalid memory size
4 warnings Warning conditions Crypto operation failed
5 noti?¬?cations Normal but signi?¬?cant
conditions
Interface changed state, up or
down
6 informational Informational messages Packet denied by ACL (default)
7 debugging Debugging messages Packet type invalid
Con?¬?guring an SNMP Managed Node 123
Setting a level means you will get that level and everything below it.
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