Technical Documentation

Monitoring the Current State of IP Routing Tables

Purpose

Display the current state of the routing table, including routes not used for forwarding.

You can display all routes, a specific route, best route to a resolved domain name, all routes beginning with a specified address, routes for a particular protocol (BGP, IS-IS, OSPF, or RIP), locally connected routes, internal control routes, static routes, or summary counters for the routing table.

Action

To display only the best routes that are used for forwarding:

host1#show ip route
Protocol/Route type codes:
  I1- ISIS level 1, I2- ISIS level2,
  I- route type intra, IA- route type inter, E- route type external,
  i- metric type internal, e- metric type external,
  O- OSPF, E1- external type 1, E2- external type2,
  N1- NSSA external type1, N2- NSSA external type2
  L- MPLS label, V- VR/VRF, *- indirect next-hop

  Prefix/Length    Type    Next Hop       Dist/Met   Intf
  -------------    ----    --------       --------   ------
  172.16.2.0/24     Bgp     192.168.1.102   20/1       fastEthernet0/0
  10.10.0.112/32    Static  192.168.1.1     1/1        fastEthernet0/0
  10.1.1.0/24       Connect 10.1.1.1        0/1        atm3/0.100

To display only the static routes from the routing table:

host1#show ip route static
Protocol/Route type codes:
  I1- ISIS level 1, I2- ISIS level2,
  I- route type intra, IA- route type inter, E- route type external,
  i- metric type internal, e- metric type external,
  O- OSPF, E1- external type 1, E2- external type2,
  N1- NSSA external type1, N2- NSSA external type2
  L- MPLS label, V- VR/VRF, *- indirect next-hop

 Prefix/Length  Type   Next Hop   Dist/Met  Intf
 -------------  ----   --------   --------  --------------
10.10.0.112/32  Static 192.168.1.1  1/1     fastEthernet0/0

To display the summary information for all routes available in the routing table:

host1#show ip route summary
Unicast routes:
8 total routes, 576 bytes in route entries
0 isis routes
0 rip routes
3 static routes
2 connected routes
1 bgp routes
0 ospf routes
2 other internal routes
0 access routes
0 internally created access host routes

Last route added/deleted: 2::4/128 by BGP
At MON FEB 04 2008 14:18:25 UTC

Unicast routes used only for Multicast RPF check:
0 total routes, 0 bytes in route entries
0 isis routes
0 rip routes
0 static routes
0 connected routes
0 bgp routes
0 ospf routes
0 other internal routes
0 access routes
0 internally created access host routes
0 mbgp routes 
0 dvmrp routes

Last route added/deleted: null by Invalid
At MON FEB 04 2008 14:18:04 UTC

MPLS tunnel routes (not used for forwarding):
3 total routes, 216 bytes in route entries
1 bgp tunnel routes
1 ldp tunnel routes
1 rsvp tunnel routes

Last route added/deleted: 2::4/128 by BGP Tunnel
At MON FEB 04 2008 14:18:26 UTC

To display all routes in the routing table inserted from all protocols (not just the best routes that are used for forwarding):

host1#show ip route all
Protocol/Route type codes:
  I1- ISIS level 1, I2- ISIS level2,
  I- route type intra, IA- route type inter, E- route type external,
  i- metric type internal, e- metric type external,
  O- OSPF, E1- external type 1, E2- external type2,
  N1- NSSA external type1, N2- NSSA external type2
  L- MPLS label, V- VR/VRF, *- indirect next-hop

  Prefix/Length      Type     Next Hop    Dist/Met    Intf
  -------------      ----     --------    --------    ------
0.0.0.0/0        Static  192.168.1.1      1/1        fastEthernet0/0
1.1.1.1/32       I2-E-i  192.168.1.105    115/10     fastEthernet0/0
6.6.6.0/24       Static  192.168.1.1      1/1        fastEthernet0/0
6.33.5.0/24      Static  0.0.0.0          1/1        loopback2
8.8.8.0/24       I2-E-i  192.168.1.105    115/10     fastEthernet0/0
9.9.9.9/32       I2-E-i  192.168.1.105    115/10     fastEthernet0/0
10.0.0.0/8       I2-E-i  192.168.1.105    115/10     fastEthernet0/0
10.10.0.156/32   Static  192.168.1.1      1/1        fastEthernet0/0
11.1.1.1/32      I2-E-i  192.168.1.105    115/10     fastEthernet0/0
11.11.11.12/32   I2-I-i  192.168.1.105    115/10     fastEthernet0/0
22.2.0.0/16      I2-I-i  92.168.1.105     115/10     fastEthernet0/0
34.0.0.0/8       I2-E-i  192.168.1.105    115/10     fastEthernet0/0
172.20.32.0/24   Static  192.168.1.1      1/1        fastEthernet0/0
174.20.32.0/24   I2-I-i  192.168.1.105    115/20     fastEthernet0/0
176.20.32.0/24   Connect 176.20.32.1      0/1        loopback1
192.168.1.0/24   Connect 192.168.1.214    0/1        fastEthernet0/0
201.1.1.0/24     I2-E-i  192.168.1.105    115/10     fastEthernet0/0
201.2.1.0/24     I2-E-i  192.168.1.105    115/10     fastEthernet0/0
201.3.1.0/24     I2-E-i  192.168.1.105    115/10     fastEthernet0/0
202.1.1.1/32     I2-E-i  192.168.1.105    115/10     fastEthernet0/0
207.1.1.0/24     I2-E-i  192.168.1.105    115/10     fastEthernet0/0

To display only the best routes that are used for forwarding (after adding routes with indirect hop):

host1#show ip route
Protocol/Route type codes:
  I1- ISIS level 1, I2- ISIS level2,
  I- route type intra, IA- route type inter, E- route type external,
  i- metric type internal, e- metric type external,
  O- OSPF, E1- external type 1, E2- external type2,
  N1- NSSA external type1, N2- NSSA external type2
  L- MPLS label, V- VR/VRF, *- indirect next-hop
 
Prefix/Length     Type     Next Hop      Dst/Met        Intf          
--------------- ------- --------------- --------- -------------------
21.21.21.2/32     Static  0.0.0.0         1/0        loopback0[V:pe2]
2.2.2.2/32        O-I     30.30.30.2      110/3      ATM2/0.30               
                          31.31.31.2      110/3      ATM2/0.31               
10.10.10.0/24     Connect 10.10.10.1      0/0        ATM2/0.10               
20.20.20.0/24     Connect 20.20.20.1      0/0        ATM2/0.21            
4.4.4.4/32        Bgp     2.2.2.2*        200/2      
                          3.3.3.3*        200/2      
5.5.5.5/32        Bgp     4.4.4.4*        20/2

To display detailed information about a specific route:

host1#show ip route 4.4.4.4 detail
Protocol/Route type codes:
  I1- ISIS level 1, I2- ISIS level2,
  I- route type intra, IA- route type inter, E- route type external,
  i- metric type internal, e- metric type external,
  O- OSPF, E1- external type 1, E2- external type2,
  N1- NSSA external type1, N2- NSSA external type2
  L- MPLS label, V- VRF
4.4.4.4/32   Type: Bgp   Distance: 200   Metric: 0   Tag: 0
   Indirect NHop: virtual-router: pe1 
   Address 1.1.1.1 Type Bgp Index 1
      NHop: 10.10.10.2 IfIndx: 28 Intf: ATM2/0.10 
      NHop: 20.20.20.2 IfIndx: 28 Intf: ATM2/0.20 
 
   Indirect NHop: virtual-router: pe1
   Address 2.2.2.2 Type Bgp Index 2
      NHop: 10.10.10.2 IfIndx: 28 Intf: ATM2/0.10 
      NHop: 20.20.20.2 IfIndx: 28 Intf: ATM2/0.20

Meaning

Table 1 lists the show ip route command output fields.

Table 1: show ip route Output Fields

Field Name	Field Description
Protocol/Route type codes	Protocol and route type codes for the table that follows
Prefix	IP address prefix of network destination
Length	Network mask length for prefix
Next Hop	IP address of the next hop to the route, whether it is a local interface or another router
Dist	Administrative distance for the route
Met	Number of hops
Intf	Interface type and interface specifier

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