Information Technology Reference
In-Depth Information
where the parameters are as follows:
minutes
: Integer that specifies the number of minutes
■
seconds
(optional): Additional time intervals in seconds
■
In a lab environment, you can specify “no timeout” by entering the
exec-timeout 0 0
com-
mand. This command is helpful because the default timeout for lines is 10 minutes.
However, for security purposes, you would not normally set lines to “no timeout” in a pro-
duction environment.
R1 is shown here as an example.
Add
exec-timeout 0 0
to console and virtual terminal lines on all routers:
R1(config)#
line console 0
R1(config-line)#
exec-timeout 0 0
R1(config-line)#
line vty 0 4
R1(config-line)#
exec-timeout 0 0
Task 3: Interpreting Debug Output
Note:
If you already configured IP addressing on R1, please remove all
interface
commands now before pro-
ceeding. R1, R2, and R3 should be configured through the end of Task 2 without any interface configurations.
On R1 from privileged EXEC mode, enter the
debug ip routing
command:
Step 1.
R1#
debug ip routing
IP routing debugging is on
The
debug ip routing
command shows when routes are added, modified, and deleted from
the routing table. For example, every time you successfully configure and activate an inter-
face, Cisco IOS adds a route to the routing table. You can verify this by observing output
from the
debug ip routing
command.
Enter interface configuration mode for R1's LAN interface.
Step 2.
R1#
configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
R1(config)#
interface fastethernet 0/0
Configure the IP address as specified in the topology diagram.
R1(config-if)#
ip address 172.16.3.1 255.255.255.0
is_up: 0 state: 6 sub state: 1 line: 1 has_route: False
As soon as you press
Enter
, Cisco IOS debug output informs you that there is now a
route, but its state is False. In other words, the route has not yet been added to the routing
table. Why did this occur and what steps should be taken to ensure that the route is entered
into the routing table?
The route cannot be entered into the routing table until the interface is activated with the
no shutdown
command.
