The Lazy Networker

In the Static routing there is one key word permanent is there, lets check the significance of that.

If the exit interface is Down then the route will also removed from the table so in some cases we want to keep the routes in the table even if the exit interface is down. For that we are using Permanent key word , lets check it in our lab
10.0.0.0/8 is variably subnetted, 4 subnets, 2 masks
S 10.2.2.0/24 [1/0] via 172.16.12.2
S 10.3.3.0/24 is directly connected, Serial1/0
172.16.0.0/16 is variably subnetted, 3 subnets, 2 masks
S 172.16.23.0/30 [1/0] via 172.16.12.2

here all those Static routes are present and i am going to shutdown the S1/0 interface

R1(config-if)#
*Sep 19 15:59:48.137: %LINK-5-CHANGED: Interface Serial1/0, changed state to administratively down
*Sep 19 15:59:49.143: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial1/0, changed state to down

R1#show ip route static

Gateway of last resort is not set

R1#

See nothing is there

Now i am going to add permanent keyword with one Static route
R1(config)#ip route 10.3.3.0 255.255.255.0 s1/0 permanent

R1#show ip route static

Gateway of last resort is not set

10.0.0.0/8 is variably subnetted, 3 subnets, 2 masks
S 10.3.3.0/24 is directly connected, Serial1/0

See that route is present and rest of all are gone.