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Re: ospf-- default-information originate vs redist static [7:42294] posted 04/23/2002
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Here's what I did:

1) Configured OSPF between a number of routers.  Verified
all where seeing routes via OSPF.

2) Made the following config additions:
	
	ip route 0.0.0.0 0.0.0.0 a.b.c.d
	ip route 1.2.3.4 255.255.255.255 a.b.c.d
	router ospf 100
 	  redistribute static subnets

where a.b.c.d is a valid next-hop

then did a show ip route on the other ospf routers.  None show
the default route but all show an E2 1.2.3.4/32 route.

3) Removed the "redistribute static subnets".  Did a 
show ip route on the other routers.  The 1.2.3.4/32
subnet disappeared.

4) Added a "default-information originate".  Did a show
ip route on the other OSPF routers and the 0/0 default appears
as an E2 route.

Cisco doesn't (apparently) treat a 0/0 route as a real route/subnet. 
For
instance, suppose you have a default route defined on a router.  Then
do a "show ip route 4.5.6.7".  If you don't have a prefix which
covers this subnet, one might expect it to report the 0/0 
resultant route.  IMO, this is what it should do.  It instead shows a
"network not in table" error.

Still learning....


	

Audy Bautista wrote:
> 
> The other day, I simulated the same sceanario but I got opposite results.
> When I first added the "default-information originate" after I added a
> default router (ip route 0.0.0.0 .0.0.0.0 a.b.c.d), the default route did
> not propagate through my OSPF network.  But, when I took of that statement
> and added the "restribute static subnets" statement, it propagated
> successfully.
> 
> Did you add a static default route (ip route 0.0.0.0 .0.0.0.0 a.b.c.d)
> before you tried the "default-information originate" statement?
> 
> ""bergenpeak""  wrote in message
> news:200204191145.HAA27750@xxxxxxxxxxxxxxxxx
> > Trying to understand OSPF behavior when generating a default
> > route.
> >
> > If I do a "default-information originate" in OSPF, I see a
> > E2 0/0 route on all other OSPF routers.  Ok, I understand this.
> >
> > If I instead define a static default route
> > "ip route 0.0.0.0 0.0.0.0 a.b.c.d" and then in my OSPF
> > setup do a "redistribute static subnets" (and not the
> > default information originate), then the other routers
> > do not see a 0/0 route.
> >
> > Why?
> >
> > THanks




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