Back to the Basics – Fun with the Routing Table

Standard

Just for some Friday night fun….

Let’s look into some of the options that are available in the show ip route command that everyone may not be aware of.

For easy reference lets have a look at all the routes I have in my lab, basically there is a bunch of BGP, RIP, OSPF, EIGRP, and a static route so it doesn’t feel left out.

R01#show ip route | begin Gateway
Gateway of last resort is not set

      1.0.0.0/24 is subnetted, 50 subnets
B        1.1.1.0 [20/5] via 10.0.254.254, 00:15:10
B        1.1.2.0 [20/5] via 10.0.254.254, 00:15:10
B        1.1.3.0 [20/5] via 10.0.254.254, 00:15:10
B        1.1.4.0 [20/5] via 10.0.254.254, 00:15:10
B        1.1.5.0 [20/5] via 10.0.254.254, 00:15:10
B        1.1.6.0 [20/5] via 10.0.254.254, 00:15:10
B        1.1.7.0 [20/5] via 10.0.254.254, 00:15:10
B        1.1.8.0 [20/5] via 10.0.254.254, 00:15:10
B        1.1.9.0 [20/5] via 10.0.254.254, 00:15:10
B        1.1.10.0 [20/5] via 10.0.254.254, 00:15:10
B        1.1.11.0 [20/5] via 10.0.254.254, 00:15:10
B        1.1.12.0 [20/5] via 10.0.254.254, 00:15:10
B        1.1.13.0 [20/5] via 10.0.254.254, 00:15:10
B        1.1.14.0 [20/5] via 10.0.254.254, 00:15:10
B        1.1.15.0 [20/5] via 10.0.254.254, 00:15:10
B        1.1.16.0 [20/5] via 10.0.254.254, 00:15:10
B        1.1.17.0 [20/5] via 10.0.254.254, 00:15:10
B        1.1.18.0 [20/5] via 10.0.254.254, 00:15:10
B        1.1.19.0 [20/5] via 10.0.254.254, 00:15:10
B        1.1.20.0 [20/5] via 10.0.254.254, 00:15:10
B        1.1.21.0 [20/5] via 10.0.254.254, 00:15:10
B        1.1.22.0 [20/5] via 10.0.254.254, 00:15:10
B        1.1.23.0 [20/5] via 10.0.254.254, 00:15:10
B        1.1.24.0 [20/5] via 10.0.254.254, 00:15:10
B        1.1.25.0 [20/5] via 10.0.254.254, 00:15:10
B        1.1.26.0 [20/5] via 10.0.254.254, 00:15:10
B        1.1.27.0 [20/5] via 10.0.254.254, 00:15:10
B        1.1.28.0 [20/5] via 10.0.254.254, 00:15:10
B        1.1.29.0 [20/5] via 10.0.254.254, 00:15:10
B        1.1.30.0 [20/5] via 10.0.254.254, 00:15:10
B        1.1.31.0 [20/5] via 10.0.254.254, 00:15:10
B        1.1.32.0 [20/5] via 10.0.254.254, 00:15:10
B        1.1.33.0 [20/5] via 10.0.254.254, 00:15:10
B        1.1.34.0 [20/5] via 10.0.254.254, 00:15:11
B        1.1.35.0 [20/5] via 10.0.254.254, 00:15:11
B        1.1.36.0 [20/5] via 10.0.254.254, 00:15:11
B        1.1.37.0 [20/5] via 10.0.254.254, 00:15:11
B        1.1.38.0 [20/5] via 10.0.254.254, 00:15:11
B        1.1.39.0 [20/5] via 10.0.254.254, 00:15:11
B        1.1.40.0 [20/5] via 10.0.254.254, 00:15:11
B        1.1.41.0 [20/5] via 10.0.254.254, 00:15:11
B        1.1.42.0 [20/5] via 10.0.254.254, 00:15:11
B        1.1.43.0 [20/5] via 10.0.254.254, 00:15:11
B        1.1.44.0 [20/5] via 10.0.254.254, 00:15:11
B        1.1.45.0 [20/5] via 10.0.254.254, 00:15:11
B        1.1.46.0 [20/5] via 10.0.254.254, 00:15:11
B        1.1.47.0 [20/5] via 10.0.254.254, 00:15:11
B        1.1.48.0 [20/5] via 10.0.254.254, 00:15:11
B        1.1.49.0 [20/5] via 10.0.254.254, 00:15:11
B        1.1.50.0 [20/5] via 10.0.254.254, 00:15:11
      2.0.0.0/24 is subnetted, 50 subnets
B        2.2.2.0 [20/8] via 10.0.254.254, 00:15:10
B        2.2.3.0 [20/8] via 10.0.254.254, 00:15:10
B        2.2.4.0 [20/8] via 10.0.254.254, 00:15:10
B        2.2.5.0 [20/8] via 10.0.254.254, 00:15:10
B        2.2.6.0 [20/8] via 10.0.254.254, 00:15:10
B        2.2.7.0 [20/8] via 10.0.254.254, 00:15:10
B        2.2.8.0 [20/8] via 10.0.254.254, 00:15:10
B        2.2.9.0 [20/8] via 10.0.254.254, 00:15:10
B        2.2.10.0 [20/8] via 10.0.254.254, 00:15:10
B        2.2.11.0 [20/8] via 10.0.254.254, 00:15:10
B        2.2.12.0 [20/8] via 10.0.254.254, 00:15:10
B        2.2.13.0 [20/8] via 10.0.254.254, 00:15:10
B        2.2.14.0 [20/8] via 10.0.254.254, 00:15:10
B        2.2.15.0 [20/8] via 10.0.254.254, 00:15:10
B        2.2.16.0 [20/8] via 10.0.254.254, 00:15:10
B        2.2.17.0 [20/8] via 10.0.254.254, 00:15:10
B        2.2.18.0 [20/8] via 10.0.254.254, 00:15:10
B        2.2.19.0 [20/8] via 10.0.254.254, 00:15:10
B        2.2.20.0 [20/8] via 10.0.254.254, 00:15:10
B        2.2.21.0 [20/8] via 10.0.254.254, 00:15:10
B        2.2.22.0 [20/8] via 10.0.254.254, 00:15:10
B        2.2.23.0 [20/8] via 10.0.254.254, 00:15:10
B        2.2.24.0 [20/8] via 10.0.254.254, 00:15:10
B        2.2.25.0 [20/8] via 10.0.254.254, 00:15:10
B        2.2.26.0 [20/8] via 10.0.254.254, 00:15:10
B        2.2.27.0 [20/8] via 10.0.254.254, 00:15:10
B        2.2.28.0 [20/8] via 10.0.254.254, 00:15:10
B        2.2.29.0 [20/8] via 10.0.254.254, 00:15:10
B        2.2.30.0 [20/8] via 10.0.254.254, 00:15:10
B        2.2.31.0 [20/8] via 10.0.254.254, 00:15:10
B        2.2.32.0 [20/8] via 10.0.254.254, 00:15:10
B        2.2.33.0 [20/8] via 10.0.254.254, 00:15:10
B        2.2.34.0 [20/8] via 10.0.254.254, 00:15:10
B        2.2.35.0 [20/8] via 10.0.254.254, 00:15:10
B        2.2.36.0 [20/8] via 10.0.254.254, 00:15:10
B        2.2.37.0 [20/8] via 10.0.254.254, 00:15:10
B        2.2.38.0 [20/8] via 10.0.254.254, 00:15:10
B        2.2.39.0 [20/8] via 10.0.254.254, 00:15:10
B        2.2.40.0 [20/8] via 10.0.254.254, 00:15:10
B        2.2.41.0 [20/8] via 10.0.254.254, 00:15:10
B        2.2.42.0 [20/8] via 10.0.254.254, 00:15:10
B        2.2.43.0 [20/8] via 10.0.254.254, 00:15:10
B        2.2.44.0 [20/8] via 10.0.254.254, 00:15:10
B        2.2.45.0 [20/8] via 10.0.254.254, 00:15:10
B        2.2.46.0 [20/8] via 10.0.254.254, 00:15:10
B        2.2.47.0 [20/8] via 10.0.254.254, 00:15:10
B        2.2.48.0 [20/8] via 10.0.254.254, 00:15:10
B        2.2.49.0 [20/8] via 10.0.254.254, 00:15:10
B        2.2.50.0 [20/8] via 10.0.254.254, 00:15:10
B        2.2.51.0 [20/8] via 10.0.254.254, 00:15:10
      3.0.0.0/24 is subnetted, 50 subnets
B        3.3.3.0 [20/0] via 10.0.254.254, 00:15:11
B        3.3.4.0 [20/0] via 10.0.254.254, 00:15:11
B        3.3.5.0 [20/0] via 10.0.254.254, 00:15:11
B        3.3.6.0 [20/0] via 10.0.254.254, 00:15:11
B        3.3.7.0 [20/0] via 10.0.254.254, 00:15:11
B        3.3.8.0 [20/0] via 10.0.254.254, 00:15:11
B        3.3.9.0 [20/0] via 10.0.254.254, 00:15:11
B        3.3.10.0 [20/0] via 10.0.254.254, 00:15:11
B        3.3.11.0 [20/0] via 10.0.254.254, 00:15:11
B        3.3.12.0 [20/0] via 10.0.254.254, 00:15:11
B        3.3.13.0 [20/0] via 10.0.254.254, 00:15:11
B        3.3.14.0 [20/0] via 10.0.254.254, 00:15:11
B        3.3.15.0 [20/0] via 10.0.254.254, 00:15:11
B        3.3.16.0 [20/0] via 10.0.254.254, 00:15:11
B        3.3.17.0 [20/0] via 10.0.254.254, 00:15:11
B        3.3.18.0 [20/0] via 10.0.254.254, 00:15:11
B        3.3.19.0 [20/0] via 10.0.254.254, 00:15:11
B        3.3.20.0 [20/0] via 10.0.254.254, 00:15:11
B        3.3.21.0 [20/0] via 10.0.254.254, 00:15:11
B        3.3.22.0 [20/0] via 10.0.254.254, 00:15:11
B        3.3.23.0 [20/0] via 10.0.254.254, 00:15:11
B        3.3.24.0 [20/0] via 10.0.254.254, 00:15:11
B        3.3.25.0 [20/0] via 10.0.254.254, 00:15:11
B        3.3.26.0 [20/0] via 10.0.254.254, 00:15:11
B        3.3.27.0 [20/0] via 10.0.254.254, 00:15:11
B        3.3.28.0 [20/0] via 10.0.254.254, 00:15:11
B        3.3.29.0 [20/0] via 10.0.254.254, 00:15:11
B        3.3.30.0 [20/0] via 10.0.254.254, 00:15:11
B        3.3.31.0 [20/0] via 10.0.254.254, 00:15:11
B        3.3.32.0 [20/0] via 10.0.254.254, 00:15:11
B        3.3.33.0 [20/0] via 10.0.254.254, 00:15:11
B        3.3.34.0 [20/0] via 10.0.254.254, 00:15:11
B        3.3.35.0 [20/0] via 10.0.254.254, 00:15:11
B        3.3.36.0 [20/0] via 10.0.254.254, 00:15:11
B        3.3.37.0 [20/0] via 10.0.254.254, 00:15:11
B        3.3.38.0 [20/0] via 10.0.254.254, 00:15:11
B        3.3.39.0 [20/0] via 10.0.254.254, 00:15:11
B        3.3.40.0 [20/0] via 10.0.254.254, 00:15:11
B        3.3.41.0 [20/0] via 10.0.254.254, 00:15:11
B        3.3.42.0 [20/0] via 10.0.254.254, 00:15:11
B        3.3.43.0 [20/0] via 10.0.254.254, 00:15:11
B        3.3.44.0 [20/0] via 10.0.254.254, 00:15:11
B        3.3.45.0 [20/0] via 10.0.254.254, 00:15:11
B        3.3.46.0 [20/0] via 10.0.254.254, 00:15:11
B        3.3.47.0 [20/0] via 10.0.254.254, 00:15:11
B        3.3.48.0 [20/0] via 10.0.254.254, 00:15:11
B        3.3.49.0 [20/0] via 10.0.254.254, 00:15:11
B        3.3.50.0 [20/0] via 10.0.254.254, 00:15:11
B        3.3.51.0 [20/0] via 10.0.254.254, 00:15:11
B        3.3.52.0 [20/0] via 10.0.254.254, 00:15:11
      10.0.0.0/8 is variably subnetted, 12 subnets, 3 masks
D        10.0.0.0/16 [90/3072] via 10.1.3.3, 00:10:06, GigabitEthernet2.13
C        10.0.254.0/24 is directly connected, GigabitEthernet2.254
L        10.0.254.1/32 is directly connected, GigabitEthernet2.254
C        10.1.2.0/24 is directly connected, GigabitEthernet2.12
L        10.1.2.1/32 is directly connected, GigabitEthernet2.12
C        10.1.3.0/24 is directly connected, GigabitEthernet2.13
L        10.1.3.1/32 is directly connected, GigabitEthernet2.13
C        10.1.4.0/24 is directly connected, GigabitEthernet2.14
L        10.1.4.1/32 is directly connected, GigabitEthernet2.14
C        10.255.0.0/24 is directly connected, Loopback0
L        10.255.0.11/32 is directly connected, Loopback0
O        10.255.0.22/32 [110/2] via 10.1.2.2, 00:07:08, GigabitEthernet2.12
O     192.168.20.0/24 [110/2] via 10.1.2.2, 00:00:01, GigabitEthernet2.12
O     192.168.21.0/24 [110/2] via 10.1.2.2, 00:00:01, GigabitEthernet2.12
O     192.168.22.0/24 [110/2] via 10.1.2.2, 00:00:01, GigabitEthernet2.12
O     192.168.23.0/24 [110/2] via 10.1.2.2, 00:00:01, GigabitEthernet2.12
O     192.168.24.0/24 [110/2] via 10.1.2.2, 00:00:01, GigabitEthernet2.12
O     192.168.25.0/24 [110/2] via 10.1.2.2, 00:00:01, GigabitEthernet2.12
O     192.168.26.0/24 [110/2] via 10.1.2.2, 00:00:01, GigabitEthernet2.12
O     192.168.27.0/24 [110/2] via 10.1.2.2, 00:00:01, GigabitEthernet2.12
O     192.168.28.0/24 [110/2] via 10.1.2.2, 00:00:01, GigabitEthernet2.12
D     192.168.30.0/24 [90/130816] via 10.1.3.3, 00:06:36, GigabitEthernet2.13
D     192.168.31.0/24 [90/130816] via 10.1.3.3, 00:06:36, GigabitEthernet2.13
D     192.168.32.0/24 [90/130816] via 10.1.3.3, 00:06:36, GigabitEthernet2.13
D     192.168.33.0/24 [90/130816] via 10.1.3.3, 00:06:36, GigabitEthernet2.13
D     192.168.34.0/24 [90/130816] via 10.1.3.3, 00:06:36, GigabitEthernet2.13
D     192.168.35.0/24 [90/130816] via 10.1.3.3, 00:06:36, GigabitEthernet2.13
D     192.168.36.0/24 [90/130816] via 10.1.3.3, 00:06:36, GigabitEthernet2.13
D     192.168.37.0/24 [90/130816] via 10.1.3.3, 00:06:36, GigabitEthernet2.13
D     192.168.38.0/24 [90/130816] via 10.1.3.3, 00:06:36, GigabitEthernet2.13
D     192.168.39.0/24 [90/130816] via 10.1.3.3, 00:06:34, GigabitEthernet2.13
R     192.168.40.0/24 [120/1] via 10.1.4.4, 00:00:22, GigabitEthernet2.14
R     192.168.41.0/24 [120/1] via 10.1.4.4, 00:00:22, GigabitEthernet2.14
R     192.168.42.0/24 [120/1] via 10.1.4.4, 00:00:22, GigabitEthernet2.14
R     192.168.43.0/24 [120/1] via 10.1.4.4, 00:00:22, GigabitEthernet2.14
R     192.168.44.0/24 [120/1] via 10.1.4.4, 00:00:22, GigabitEthernet2.14
R     192.168.45.0/24 [120/1] via 10.1.4.4, 00:00:22, GigabitEthernet2.14
R     192.168.46.0/24 [120/1] via 10.1.4.4, 00:00:22, GigabitEthernet2.14
R     192.168.47.0/24 [120/1] via 10.1.4.4, 00:00:22, GigabitEthernet2.14
R     192.168.48.0/24 [120/1] via 10.1.4.4, 00:00:22, GigabitEthernet2.14
R     192.168.49.0/24 [120/1] via 10.1.4.4, 00:00:22, GigabitEthernet2.14
S     192.168.50.0/24 [1/0] via 10.1.2.2
R01#  

One of the easiest ways to filter the routing table is tell the router what types of routes we want to see. We can see all the local interface routes by looking at the connected routes.

R01#show ip route connect | be Gateway
Gateway of last resort is not set

      10.0.0.0/8 is variably subnetted, 12 subnets, 3 masks
C        10.0.254.0/24 is directly connected, GigabitEthernet2.254
L        10.0.254.1/32 is directly connected, GigabitEthernet2.254
C        10.1.2.0/24 is directly connected, GigabitEthernet2.12
L        10.1.2.1/32 is directly connected, GigabitEthernet2.12
C        10.1.3.0/24 is directly connected, GigabitEthernet2.13
L        10.1.3.1/32 is directly connected, GigabitEthernet2.13
C        10.1.4.0/24 is directly connected, GigabitEthernet2.14
L        10.1.4.1/32 is directly connected, GigabitEthernet2.14
C        10.255.0.0/24 is directly connected, Loopback0
L        10.255.0.11/32 is directly connected, Loopback0

We can also look at particular protocol routes as well. Here is OSPF:

R01#show ip route ospf | be Gateway   
Gateway of last resort is not set

      10.0.0.0/8 is variably subnetted, 12 subnets, 3 masks
O        10.255.0.22/32 [110/2] via 10.1.2.2, 00:00:01, GigabitEthernet2.12
O     192.168.20.0/24 [110/2] via 10.1.2.2, 00:00:01, GigabitEthernet2.12
O     192.168.21.0/24 [110/2] via 10.1.2.2, 00:00:01, GigabitEthernet2.12
O     192.168.22.0/24 [110/2] via 10.1.2.2, 00:00:01, GigabitEthernet2.12
O     192.168.23.0/24 [110/2] via 10.1.2.2, 00:00:01, GigabitEthernet2.12
O     192.168.24.0/24 [110/2] via 10.1.2.2, 00:00:01, GigabitEthernet2.12
O     192.168.25.0/24 [110/2] via 10.1.2.2, 00:00:01, GigabitEthernet2.12
O     192.168.26.0/24 [110/2] via 10.1.2.2, 00:00:01, GigabitEthernet2.12
O     192.168.27.0/24 [110/2] via 10.1.2.2, 00:00:01, GigabitEthernet2.12
O     192.168.28.0/24 [110/2] via 10.1.2.2, 00:00:01, GigabitEthernet2.12

Here is EIGRP

R01#show ip route eigrp | be Gateway
Gateway of last resort is not set

      10.0.0.0/8 is variably subnetted, 12 subnets, 3 masks
D        10.0.0.0/16 [90/3072] via 10.1.3.3, 00:24:47, GigabitEthernet2.13
      192.168.29.0/24 is variably subnetted, 2 subnets, 2 masks
D        192.168.29.0/24 
           [90/130816] via 10.1.3.3, 00:05:22, GigabitEthernet2.13
D     192.168.30.0/24 [90/130816] via 10.1.3.3, 00:21:15, GigabitEthernet2.13
D     192.168.31.0/24 [90/130816] via 10.1.3.3, 00:21:15, GigabitEthernet2.13
D     192.168.32.0/24 [90/130816] via 10.1.3.3, 00:21:15, GigabitEthernet2.13
D     192.168.33.0/24 [90/130816] via 10.1.3.3, 00:21:15, GigabitEthernet2.13
D     192.168.34.0/24 [90/130816] via 10.1.3.3, 00:21:15, GigabitEthernet2.13
D     192.168.35.0/24 [90/130816] via 10.1.3.3, 00:21:15, GigabitEthernet2.13
D     192.168.36.0/24 [90/130816] via 10.1.3.3, 00:21:15, GigabitEthernet2.13
D     192.168.37.0/24 [90/130816] via 10.1.3.3, 00:21:15, GigabitEthernet2.13
D     192.168.38.0/24 [90/130816] via 10.1.3.3, 00:21:15, GigabitEthernet2.13
D     192.168.39.0/24 [90/130816] via 10.1.3.3, 00:21:13, GigabitEthernet2.13

and RIP, I’ll skip BGP but you get the idea

R01#show ip route rip | be Gateway  
Gateway of last resort is not set

R     192.168.40.0/24 [120/1] via 10.1.4.4, 00:00:20, GigabitEthernet2.14
R     192.168.41.0/24 [120/1] via 10.1.4.4, 00:00:20, GigabitEthernet2.14
R     192.168.42.0/24 [120/1] via 10.1.4.4, 00:00:20, GigabitEthernet2.14
R     192.168.43.0/24 [120/1] via 10.1.4.4, 00:00:20, GigabitEthernet2.14
R     192.168.44.0/24 [120/1] via 10.1.4.4, 00:00:20, GigabitEthernet2.14
R     192.168.45.0/24 [120/1] via 10.1.4.4, 00:00:20, GigabitEthernet2.14
R     192.168.46.0/24 [120/1] via 10.1.4.4, 00:00:20, GigabitEthernet2.14
R     192.168.47.0/24 [120/1] via 10.1.4.4, 00:00:20, GigabitEthernet2.14
R     192.168.48.0/24 [120/1] via 10.1.4.4, 00:00:20, GigabitEthernet2.14
R     192.168.49.0/24 [120/1] via 10.1.4.4, 00:00:20, GigabitEthernet2.14

Aside from filtering on protocols we can also do some IP filtering, we can filter by the classful subnet though it isn’t all that useful for Class C routes if you are using /24s.

R01#show ip route 1.0.0.0
Routing entry for 1.0.0.0/24, 50 known subnets
B        1.1.1.0 [20/5] via 10.0.254.254, 00:43:24
B        1.1.2.0 [20/5] via 10.0.254.254, 00:43:24
B        1.1.3.0 [20/5] via 10.0.254.254, 00:43:24
B        1.1.4.0 [20/5] via 10.0.254.254, 00:43:24
B        1.1.5.0 [20/5] via 10.0.254.254, 00:43:24
B        1.1.6.0 [20/5] via 10.0.254.254, 00:43:24
B        1.1.7.0 [20/5] via 10.0.254.254, 00:43:24
B        1.1.8.0 [20/5] via 10.0.254.254, 00:43:24
B        1.1.9.0 [20/5] via 10.0.254.254, 00:43:24
B        1.1.10.0 [20/5] via 10.0.254.254, 00:43:24
B        1.1.11.0 [20/5] via 10.0.254.254, 00:43:24
B        1.1.12.0 [20/5] via 10.0.254.254, 00:43:24
B        1.1.13.0 [20/5] via 10.0.254.254, 00:43:24
B        1.1.14.0 [20/5] via 10.0.254.254, 00:43:24
B        1.1.15.0 [20/5] via 10.0.254.254, 00:43:24
B        1.1.16.0 [20/5] via 10.0.254.254, 00:43:24
B        1.1.17.0 [20/5] via 10.0.254.254, 00:43:24
B        1.1.18.0 [20/5] via 10.0.254.254, 00:43:24
B        1.1.19.0 [20/5] via 10.0.254.254, 00:43:24
B        1.1.20.0 [20/5] via 10.0.254.254, 00:43:24
B        1.1.21.0 [20/5] via 10.0.254.254, 00:43:24
B        1.1.22.0 [20/5] via 10.0.254.254, 00:43:24
B        1.1.23.0 [20/5] via 10.0.254.254, 00:43:24
 --More-- 

If you would prefer to filter with VLSM subnetting we can add a subnet mask and use the longer-prefixes keyword

R01#show ip route 192.168.20.0 255.255.252.0 longer-prefixes | be Gateway
Gateway of last resort is not set

O     192.168.20.0/24 [110/2] via 10.1.2.2, 00:14:46, GigabitEthernet2.12
O     192.168.21.0/24 [110/2] via 10.1.2.2, 00:14:46, GigabitEthernet2.12
O     192.168.22.0/24 [110/2] via 10.1.2.2, 00:14:46, GigabitEthernet2.12
O     192.168.23.0/24 [110/2] via 10.1.2.2, 00:14:46, GigabitEthernet2.12

If you want to see a set of particular routes like say various server routes you can specify an access-list with the list keyword

R01(config)#ip access-list standard CATS
R01(config-std-nacl)#permit 192.168.22.0 0.0.0.255
R01(config-std-nacl)#permit 192.168.32.0 0.0.0.255
R01(config-std-nacl)#permit 192.168.42.0 0.0.0.255
R01(config-std-nacl)#permit 1.1.30.0 0.0.0.255
R01(config-std-nacl)#end 

R01#show ip route list CATS
      1.0.0.0/24 is subnetted, 50 subnets
B        1.1.30.0 [20/5] via 10.0.254.254, 00:52:30
O     192.168.22.0/24 [110/2] via 10.1.2.2, 00:16:31, GigabitEthernet2.12
D     192.168.32.0/24 [90/130816] via 10.1.3.3, 00:43:52, GigabitEthernet2.13
R     192.168.42.0/24 [120/1] via 10.1.4.4, 00:00:09, GigabitEthernet2.14

The summary keyword will show…well….a summary of the routes in the routing table.

R01#show ip route  summary 
IP routing table name is default (0x0)
IP routing table maximum-paths is 32
Route Source    Networks    Subnets     Replicates  Overhead    Memory (bytes)
application     0           0           0           0           0
connected       0           10          0           960         2960
static          1           0           0           96          296
bgp 1           0           150         0           14400       44400
  External: 150 Internal: 0 Local: 0
ospf 1          9           1           0           960         3000
  Intra-area: 10 Inter-area: 0 External-1: 0 External-2: 0
  NSSA External-1: 0 NSSA External-2: 0
eigrp 100       11          1           0           1696        3552
rip             10          0           0           960         2960
internal        4                                               16544
Total           35          162         0           19072       73712

Lastly we can also see detailed route information by specifying that subnet we are looking for, this probably isn’t that useful for CCNA but you can see more route attributes if they exist.

R01#show ip route 192.168.20.0
Routing entry for 192.168.20.0/24
  Known via "ospf 1", distance 110, metric 2, type intra area
  Last update from 10.1.2.2 on GigabitEthernet2.12, 00:01:09 ago
  Routing Descriptor Blocks:
  * 10.1.2.2, from 192.168.0.2, 00:01:09 ago, via GigabitEthernet2.12
      Route metric is 2, traffic share count is 1

On the IPv6 side of the house we can use the updated keyword to show route age info

R01# show ipv6 route updated | be 110
O   2001::2/128 [110/1]
     via FE80::2, GigabitEthernet2.12
      Last updated 08:09:50 04 February 2017
O   2001::20/128 [110/1]
     via FE80::2, GigabitEthernet2.12
      Last updated 08:12:03 04 February 2017
O   2001::21/128 [110/1]
     via FE80::2, GigabitEthernet2.12
      Last updated 08:12:03 04 February 2017
O   2001::22/128 [110/1]
     via FE80::2, GigabitEthernet2.12
      Last updated 08:12:03 04 February 2017
O   2001::23/128 [110/1]
     via FE80::2, GigabitEthernet2.12
      Last updated 08:12:03 04 February 2017
O   2001::24/128 [110/1]
     via FE80::2, GigabitEthernet2.12
      Last updated 08:12:03 04 February 2017
O   2001::25/128 [110/1]
     via FE80::2, GigabitEthernet2.12
      Last updated 08:12:03 04 February 2017
O   2001::26/128 [110/1]
     via FE80::2, GigabitEthernet2.12
      Last updated 08:12:03 04 February 2017
O   2001::27/128 [110/1]
     via FE80::2, GigabitEthernet2.12
      Last updated 08:12:03 04 February 2017
O   2001::28/128 [110/1]
     via FE80::2, GigabitEthernet2.12
      Last updated 08:12:03 04 February 2017
O   2001::29/128 [110/1]
     via FE80::2, GigabitEthernet2.12
      Last updated 08:12:03 04 February 2017
C   2001:123:12::/64 [0/0]
     via GigabitEthernet2.12, directly connected
      Last updated 08:08:06 04 February 2017
L   2001:123:12::1/128 [0/0]
     via GigabitEthernet2.12, receive
      Last updated 08:08:07 04 February 2017
L   FF00::/8 [0/0]
     via Null0, receive

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