From: Alejandro Cadarso (a.cadarso@xxxxxxxxxxxxxx)
Date: Fri Sep 08 2000 - 14:08:14 GMT-3
I'm sorry I've just tried an scenario to confirm what I thought
I remembered and it isn't true. Besides:
http://www.cisco.com/warp/public/104/9.html#Q9
The command distribute-list out works only on the routes being redistributed
by the autonomous system boundary routers (ASBRs) into OSPF. It can be
applied to external type 2 and external type 1 routes, but not to
intra-area and inter-area routes.
Then what I can't understand is the example from the Doc-CD in the command
reference:
http://127.0.0.1:8080/cc/td/doc/product/software/ios100/rpcr/66004.htm#xtocid10
67224
The following example applies access list 1 to outgoing routing updates and ena
bles
IS-IS on Ethernet interface 0. Only network 131.131.101.0 will be
advertised in outgoing IS-IS routing updates.
router isis
redistribute ospf 109
distribute-list 1 out
interface Ethernet 0
ip router isis
access-list 1 permit 131.131.101.0 0.0.0.255
Is not the isis a link-state protocol?????
Alejandro.
Alejandro Cadarso wrote:
>
> Filtering information with link-state protocols such as OSPF is a
> tricky business. Distribute-list out works on the ASBR to filter
> redistributed routes into other protocols.
>
> A distribute-list only affects LSA types 3 and 5. Type 3 can be filtered at
> the ABR outbound towards area 0. Type 5 can be filtered at the ASBR outbound
> into the area or at the ABR outbound towards area 0. The reason is that LSA
> types 3 and 5 are transmitted and evaluated using distance-vector rules.
> Redistribution between two OSPF processes produces type 5 LSA's and that
> router is an ASBR for both OSPF AS's.
>
> Then your configuration must work if in Router 1:
>
> router ospf xx
> distribute-list 101 out Serial0
>
> access-list 101 deny ip 192.2.2.0 0.0.0.255 any
>
> And 192.2.2.0 doesn't belongs to Area 0
>
> Distribute-list in works on any router to prevent routes from
> being put in the routing table, but it does not prevent
> link-state packets from being propagated,then you can use it too
> in Router 2 and the route don't must to appear, but if you have any
> other routers in your area 0 they're going to see network 192.2.2.0
>
> Kenneth Kriel wrote:
> >
> > Gentleman,
> >
> > How do I filter a route from coming into OSFP ? I know it might be a stupid
> > question but I can not get it to work !
> >
> > Layout
> >
> > OSPF Area 1 Area 0
> > 192.2.2.0/24----|
> > |--R1-----R2
> > 135.1.x.0/24----|
> >
> > I do not want to see 192.2.2.0/24 on router R2 !
> >
> > I tried distribute-list out on R1 and in on R2 but no luck !
> >
> > Thank you in advance !
> >
> > Ken
> >
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