From: Bill Carter (bcarter@xxxxxxxxxxxxxx)
Date: Fri Jul 23 1999 - 15:25:28 GMT-3
After posting this question at 1:30 AM and not getting any responses (I guess
you folks have lives, I'm jealous). I called TAC about this issue. TAC gave 2
solutions:
1) Distribute-List
router ospf 1
redistribute RIP subnets 10 in
access-list 10 deny 12.0.0.0 0.0.0.255
access-list 10 deny 150.100.1.0 0.0.0.255
access-list 10 permit any
Because of the LSA issue, this solution has to be issued on every ospf router.
While the end result would prevent the routes from being placed into the route
tables, it is very clumsy. And if the route is not in the table but it is in
the database has much been gained.
2) Route-map
This solution prevents not only the route from coming into OSPF, but also into
the Database. It looks like the preferred answer is to use route-maps to filte
r
from a DV to a LS. I am not clear enough on distribution-lists to understand
why these 2 solution provide different results. What is different??
router ospf 1
redistribute rip subnets route-map test
passive-interface Ethernet0
passive-interface Serial1
network 150.100.1.0 0.0.0.255 area 0
!
router rip
redistribute ospf 1
passive-interface Serial0.1
network 150.100.0.0
default-metric 5
access-list 10 deny 12.0.0.0 0.0.0.255
access-list 10 deny 150.100.1.0 0.0.0.255
access-list 10 permit any
route-map test permit 10
match ip address 10
Ron Trunk wrote:
> >Pamela is right in that LS routing protos can't be filtered the way that DV
> >can be.
> >
>
> I agree 100%
>
> >The routes in OSPF are calculated by SPF from LSA and no routes are
> >transferred amoung routers in the area at any time. However, I think with
> >distribute-list you can filter routes that are calculated by OSPF and then
> >put INto the table. This is only effective on the local router, therefore,
> >to eliminate a route from all routers in an OSPF area you would have to put
> >this statement on all the routers. The LSAs would not be effected.
> >
>
> But if that router is the distribution router, as in Bill's case, it would
> make sense, since he is filtering routers learned from outside the domain
> (e.g. RIP). If the routes are filtered before they get into the routing
> table, OSPF won't redistribute them to the other OSPF routers.
>
> Ron
>
This archive was generated by hypermail 2.1.4 : Thu Jun 13 2002 - 08:21:42 GMT-3