Configuration Guide Vol. 3

14.3.5 Checking routes resulting from learned route filtering

Routes permitted by learned route filtering are entered into the routing table. You can check the results of learned route filtering by viewing the routes in the routing table.

To display every route in the routing table including invalid routes, execute the show ip route operation command with the all-routes parameter specified.

Figure 14-7: Example of displaying routes in the routing table (including invalid routes) 
> show ip route all-routes
Date 20XX/07/14 12:00:00 UTC
Status Codes: * valid, > active, r RIB failure
Total: 12 routes
   Destination        Next Hop       Interface    Metric  Protocol    Age
*> 127/8              ----           localhost    0/0     Connected    1h 32s-
*> 127.0.0.1/32       127.0.0.1      localhost    0/0     Connected    1h 32s|
*> 172.10.1/24        192.168.1.145  VLAN0007     2/0     RIP         12s    |
*> 192.168.1/24       192.168.1.1    VLAN0007     0/0     Connected    2s    |
   192.168.1/24       192.168.1.1    VLAN0007     1/-     OSPF intra  48m  3s|
*> 192.168.1.1/32     192.168.1.1    VLAN0007     0/0     Connected    1h 31s #
*> 200.1/24           192.168.1.145  VLAN0007     -/-     BGP         11m 26s|
*> 201.110/24         192.168.1.145  VLAN0007     1/1     OSPF ext2   52s    |
*> 200.200.1/24       192.168.1.145  VLAN0007     0/0     Static      46m 58s|
*  200.200.1/24       192.168.1.145  VLAN0007     -/-     BGP         50m 14s|
*  200.200.1/24       192.168.1.145  VLAN0007     1/1     OSPF ext2   48m 52s|
*  200.200.1/24       192.168.1.145  VLAN0007     2/0     RIP         12s    -
#

The characters * and > at the beginning of an entry signify the following:

*: Signifies a valid route. Its absence indicates an invalid route.

>: Signifies a prioritized route. Only prioritized routes are used for packet transfer.

To check only those routes that were learned by a specific protocol, execute the show ip route operation command with the all-routes parameter and the protocol specified.

Figure 14-8: Example of displaying routes in the routing table (including invalid routes for RIP only) 
> show ip route all-routes rip
Date 20XX/07/14 12:00:00 UTC
Status Codes: * valid, > active, r RIB failure
Total: 2 routes
   Destination        Next Hop        Interface      Metric   Protocol  Age
*> 172.10.1/24        192.168.1.145   VLAN0007       2/0      RIP       12s
*  200.200.1/24       192.168.1.145   VLAN0007       2/0      RIP       12s

If the various protocols generate more than one route to the same destination network, you will need to check which protocol supplied the prioritized route, and the priority of each route. The priority of each route is determined by its distance value.

To display distance values, execute the show ip route operation command with the all-routes and -P parameters specified. The distance is the first value in the Distance column at the end of each line.

Figure 14-9: Example of displaying route distance in the routing table 
> show ip route all-routes -P
Date 20XX/07/14 12:00:00 UTC
Status Codes: * valid, > active, r RIB failure
Total: 12 routes
   Destination        Next Hop       Interface    Metric   Protocol    Age
*> 127/8              ----           localhost    0/0      Connected    1h 36m,
Distance: 0/0/0
*> 127.0.0.1/32       127.0.0.1      localhost    0/0      Connected    1h 36m,
Distance: 0/0/0
*> 172.10.1/24        192.168.1.145  VLAN0007     2/0      RIP         12s,
Distance: 120/0/0
*> 192.168.1/24       192.168.1.1    VLAN0007     0/0      Connected    0s,
Distance: 0/0/0
   192.168.1/24       192.168.1.1    VLAN0007     1/-      OSPF intra  52m 32s,
Distance: -110/1/0
*> 192.168.1.1/32     192.168.1.1    VLAN0007     0/0      Connected    1h 35m,
Distance: 0/0/0
*> 200.1/24           192.168.1.145  VLAN0007     -/-      BGP         12m 37s,
Distance: 20/0/0
*> 201.110/24         192.168.1.145  VLAN0007     1/1      OSPF ext2    6m 11s,
Distance: 110/1/0 
*> 200.200.1/24       192.168.1.145  VLAN0007     0/0      Static      50m 27s,
Distance: 2/0/0
*  200.200.1/24       192.168.1.145  VLAN0007     -/-      BGP         54m 43s,
Distance: 20/0/0
*  200.200.1/24       192.168.1.145  VLAN0007     1/1      OSPF ext2   52m 21s,
Distance: 110/1/0
*  200.200.1/24       192.168.1.145  VLAN0007     2/0      RIP         12s,
Distance: 120/0/0

To display the distance values for routes to a specific destination, execute the show ip route operation command with the all-routes parameter and the destination network specified. The route's distance is the first value on the Distance line in the detailed routing information.

Figure 14-10: Example of displaying routes in the routing table (for specific destinations, including invalid routes) 
> show ip route all-routes 200.200.1/24
Date 20XX/07/14 12:00:00 UTC
Route codes: *  = active,   + = changed to active recently
            ' ' = inactive, - = changed to inactive recently
             r  = RIB failure
 
Route 200.200.1/24
Entries 4 Announced 1 Depth 0 <>
 
* NextHop 192.168.1.145  , Interface   : VLAN0007
     Protocol <Static>
     Source Gateway ----
     Metric/2    : 0/0
     Distance/2/3: 2/0/0
     Tag : 0, Age : 58m 29s
     AS Path : IGP (Id 1)
     Communities: -
     LocalPref : -
     RT State: <Remote Int Active Gateway>
 
  NextHop 192.168.1.145  , Interface   : VLAN0007
     Protocol <BGP>
     Source Gateway 192.168.1.145
     Metric/2    : -/-
     Distance/2/3: 20/0/0
     Tag : 0, Age :  1h  2m
     AS Path : 1000 IGP (Id 2)
     Communities: -
     LocalPref : 100
     RT State: <Ext Gateway>

To check detailed attribute information for routes, use the show ip route operation command with the all-routes and -F parameters specified.

Figure 14-11: Example of displaying routes in the routing table (including invalid routes and detailed information) 
> show ip route all-routes -F
Date 20XX/07/14 12:00:00 UTC
Status Codes: * valid, > active, r RIB failure
Total: 12 routes
   Destination        Next Hop       Interface    Metric   Protocol    Age
*> 127/8              ----           localhost    0/0      Connected    1h 46m,
Distance: 0/0/0, Tag: 0, AS-Path: IGP (Id 1), Communities: -, LocalPref: -, <NoAdvise Active Retain Reject>
*> 127.0.0.1/32       127.0.0.1      localhost    0/0      Connected    1h 46m,
Distance: 0/0/0, Tag: 0, AS-Path: IGP (Id 1), Communities: -, LocalPref: -, <NoAdvise Active Retain>
*> 172.10.1/24        192.168.1.145  VLAN0007     2/0      RIP         19s,
Distance: 120/0/0, Tag: 0, AS-Path: IGP (Id 1), Communities: -, LocalPref: -,<Int Active Gateway>
*> 192.168.1/24       192.168.1.1    VLAN0007     0/0      Connected    7s,
Distance: 0/0/0, Tag: 0, AS-Path: IGP (Id 1), Communities: -, LocalPref: -, <Active Retain>
   192.168.1/24       192.168.1.1    VLAN0007     1/-      OSPF intra   1h  2m,
Distance: -110/1/0, Tag: 0, AS-Path: IGP (Id 1), Communities: -, LocalPref: -, <NotInstall NoAdvise Int Hidden Gateway>
*> 177.7.7.1/32       192.168.1.1    VLAN0007     0/0      Connected    1h 45m, 
Distance: 0/0/0, Tag: 0, AS-Path: IGP (Id 1), Communities: -, LocalPref: -, <NoAdvise Active Retain>
*> 200.1/24           192.168.1.145  VLAN0007     -/-      BGP         12m 57s, 
Distance: 20/0/0, Tag: 0, AS-Path: 1000 IGP (Id 3), Communities: 120:200, LocalPref: 100, <Ext Active Gateway>
*> 201.110.1/24       192.168.1.145  VLAN0007     1/1      OSPF ext2    3m 34s, 
Distance: 110/1/0, Tag: 10, AS-Path: IGP (Id 1), Communities: -, LocalPref: -, <Int Ext Active Gateway>
*> 200.200.1/24       192.168.1.145  VLAN0007     0/0      Static       1h  0m, 
Distance: 2/0/0, Tag: 0, AS-Path: IGP (Id 1), Communities: -, LocalPref: -, <Remote Int Active Gateway>
*  200.200.1/24       192.168.1.145  VLAN0007     -/-      BGP          1h  5m, 
Distance: 20/0/0, Tag: 0, AS-Path: 1000 IGP (Id 2), Communities: -, LocalPref: 100, <Ext Gateway>
*  200.200.1/24       192.168.1.145  VLAN0007     1/1      OSPF ext2    1h  2m, 
Distance: 110/1/0, Tag: 0, AS-Path: IGP (Id 1), Communities: -, LocalPref: -,<Int Ext Gateway>
*  200.200.1/24       192.168.1.145  VLAN0007     2/0      RIP         19s, 
Distance: 120/0/0, Tag: 0, AS-Path: IGP (Id 1), Communities: -, LocalPref: -,<Int Gateway>

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