default-information originate route-map

From: Gavin Schokman <g_schokman_at_yahoo.com.au>
Date: Sat, 18 Apr 2009 23:34:29 +0100

Evening brain-bank,
 
I'm working through some IEWB lab stuff and come across an unexpected
behaviour (unexpected to me at least).
 
I'm trying to conditionally originate a default route via RIP. The condition
I'm using is "does 0.0.0.0/0 appear in local route table?".
If yes -> originate default, if not -> don't originate
 
The problem is that when I use 0.0.0.0/0 in the condition, it doesn't work.
If I use another (random) route as the condition, it works.
See config below:
 
condition_route = 0.0.0.0/0 => doesn't work
 
router rip
 version 2
 default-information originate route-map DEFAULT_MONITOR
 no auto-summary
 
ip route 0.0.0.0 0.0.0.0 Null0
 
ip prefix-list DEFAULT seq 5 permit 0.0.0.0/0
 
route-map DEFAULT_MONITOR permit 10
 match ip address prefix-list DEFAULT
 
! static route exists on Rack1R6
 
Rack1R6#sh ip route 0.0.0.0
Routing entry for 0.0.0.0/0, supernet
  Known via "static", distance 1, metric 0 (connected), candidate default
path
  Routing Descriptor Blocks:
  * directly connected, via Null0
      Route metric is 0, traffic share count is 1
 
! default is not originated and pushed via RIP to Rack1R4
 
Rack1R4#sh ip route 0.0.0.0
% Network not in table
 
condition_route = 1.1.1.1/32 => doesn't work
 
router rip
 version 2
 default-information originate route-map ROUTE_WATCH
 no auto-summary
 
ip route 1.1.1.1 255.255.255.255 Null0
 
ip prefix-list ROUTE_WATCH seq 5 permit 1.1.1.1/32
 
route-map ROUTE_WATCH permit 10
 match ip address prefix-list ROUTE_WATCH
 
! static route exists on Rack1R6

Rack1R6#sh ip route 0.0.0.0
Routing entry for 0.0.0.0/0, supernet
  Known via "static", distance 1, metric 0 (connected), candidate default
path
  Routing Descriptor Blocks:
  * directly connected, via Null0
      Route metric is 0, traffic share count is 1
 
! default IS originated and pushed via RIP to Rack1R4
 
Rack1R4#sh ip route 0.0.0.0
Routing entry for 0.0.0.0/0, supernet
  Known via "rip", distance 120, metric 1, candidate default path
  Redistributing via rip
  Last update from 155.1.146.6 on Ethernet0/1, 00:00:03 ago
  Routing Descriptor Blocks:
  * 155.1.146.6, from 155.1.146.6, 00:00:03 ago, via Ethernet0/1
      Route metric is 1, traffic share count is 1
 
 
Seems to be something strange with 0.0.0.0/0. I know it is matching, see
below
 
Rack1R6#sh ip prefix-list detail
ip prefix-list DEFAULT:
   count: 1, range entries: 0, sequences: 5 - 5, refcount: 2
   seq 5 permit 0.0.0.0/0 (hit count: 20, refcount: 1)
 
 
Any thoughts?
 
Cheers,
Gavin

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Received on Sat Apr 18 2009 - 23:34:29 ART

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