Information Technology Reference
In-Depth Information
Gateway of last resort is not set
172.16.0.0/24 is subnetted, 1 subnets
C 172.16.3.0 is directly connected, FastEthernet0/0
Enter interface configuration mode for R1's WAN interface connected to R2.
Step 5.
R1#
configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
R1(config)#
interface Serial 0/0/0
Configure the IP address as specified in the topology diagram.
R1(config-if)#
ip address 172.16.2.1 255.255.255.0
is_up: 0 state: 0 sub state: 1 line: 0 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
. Because R1 is the DCE side of the lab environment, you must
specify how fast the bits will be clocked between R1 and R2.
Enter the
clock rate
command on R1.
Step 6.
You can specify any valid clocking speed. Use the
?
to find the valid rates. Here, we used
64,000 bps.
R1(config-if)#
clock rate 64000
is_up: 0 state: 0 sub state: 1 line: 0 has_route: False
Some IOS versions display the output shown above every 30 seconds. Why is the state of
the route still
False
? What step must you now take to make sure that the interface is fully
configured?
The route cannot be entered into the routing table until the interface is activated with the
no shutdown
command.
Enter the command necessary to ensure that the interface is fully configured.
Step 7.
If you are not sure what the correct command is, review the section “Configuring and
Verifying Interfaces Exercise,” earlier in this chapter.
R1(config-if)#
no shutdown
After you enter the correct command, you should see debug output similar to the following
example:
is_up: 0 state: 0 sub state: 1 line: 0 has_route: False
%LINK-3-UPDOWN: Interface Serial0/0/0, changed state to down
Unlike configuring the LAN interface, fully configuring the WAN interface does not
always guarantee that the route will be entered in the routing table, even if your cable con-
nections are correct. The other side of the WAN link must also be configured.
