Displaying The Routing Table - Cisco ASA Series Cli Configuration Manual

Information About the Routing Table
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Displaying the Routing Table

To view the entries in the routing table, enter the following command:
hostname# show route
Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP
Gateway of last resort is 10.86.194.1 to network 0.0.0.0
S
C
S*
On the ASA 5505, the following route is also shown. It is the internal loopback interface, which is used
by the VPN hardware client feature for individual user authentication.
C 127.1.0.0 255.255.0.0 is directly connected, _internal_loopback
How the Routing Table Is Populated
The ASA routing table can be populated by statically defined routes, directly connected routes, and
routes discovered by the RIP, EIGRP, and OSPF routing protocols. Because the ASA can run multiple
routing protocols in addition to having static and connected routes in the routing table, it is possible that
the same route is discovered or entered in more than one manner. When two routes to the same
destination are put into the routing table, the one that remains in the routing table is determined as
follows:
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Cisco ASA Series CLI Configuration Guide
1-6
Dynamic Routing in Multiple Context Mode, page 1-10
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP
i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter area
* - candidate default, U - per-user static route, o - ODR
P - periodic downloaded static route
10.1.1.0 255.255.255.0 [3/0] via 10.86.194.1, outside
10.86.194.0 255.255.254.0 is directly connected, outside
0.0.0.0 0.0.0.0 [1/0] via 10.86.194.1, outside
If the two routes have different network prefix lengths (network masks), then both routes are
considered unique and are entered into the routing table. The packet forwarding logic then
determines which of the two to use.
For example, if the RIP and OSPF processes discovered the following routes:
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RIP: 192.168.32.0/24
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OSPF: 192.168.32.0/19
Even though OSPF routes have the better administrative distance, both routes are installed in the
routing table because each of these routes has a different prefix length (subnet mask). They are
considered different destinations and the packet forwarding logic determines which route to use.
If the ASA learns about multiple paths to the same destination from a single routing protocol, such
as RIP, the route with the better metric (as determined by the routing protocol) is entered into the
routing table.
Chapter 1 Routing Overview