From: Victor Cappuccio (cvictor@protokolgroup.com)
Date: Sat Jul 22 2006 - 07:09:43 ART
The AD of the summary must be 255
R6#conf te
Enter configuration commands, one per line. End with CNTL/Z.
R6(config)#int f0/0.663
R6(config-subif)#ip summa eigrp 100 0.0.0.0 0.0.0.0 5
R6(config-subif)#
*Jul 14 16:17:18.368: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor
192.168.10.
254 (FastEthernet0/0.663) is resync: summary configured
*Jul 14 16:17:18.412: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor
192.168.10.
254 (FastEthernet0/0.663) is down: peer restarted
R6(config-subif)#do sho
*Jul 14 16:17:22.066: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor
192.168.10.
254 (FastEthernet0/0.663) is up: new adjacency
R6(config-subif)#do show ip route 0.0.0.0
Routing entry for 0.0.0.0/0, supernet
Known via "eigrp 100", distance 5, metric 28160, candidate default path,
typ
e internal
Redistributing via eigrp 100, ospf 1
Routing Descriptor Blocks:
* directly connected, via Null0
Route metric is 28160, traffic share count is 1
Total delay is 100 microseconds, minimum bandwidth is 100000 Kbit
Reliability 255/255, minimum MTU 1500 bytes
Loading 1/255, Hops 0
R6(config-subif)#ip summa eigrp 100 0.0.0.0 0.0.0.0 255
R6(config-subif)#
*Jul 14 16:17:31.862: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor
192.168.10.
254 (FastEthernet0/0.663) is resync: summary configured
*Jul 14 16:17:32.159: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor
192.168.10.
254 (FastEthernet0/0.663) is down: peer restarted
R6(config-subif)#do show ip route 0.0.0.0
Routing entry for 0.0.0.0/0, supernet
Known via "eigrp 100", distance 5, metric 28160, candidate default path,
type internal
Redistributing via eigrp 100, ospf 1
Routing Descriptor Blocks:
* directly connected, via Null0
Route metric is 28160, traffic share count is 1
Total delay is 100 microseconds, minimum bandwidth is 100000 Kbit
Reliability 255/255, minimum MTU 1500 bytes
Loading 1/255, Hops 0
R6(config-subif)#do clear ip route *
R6(config-subif)#do show ip route 0.0.0.0
% Network not in table
R6(config-subif)#
-----Mensaje original-----
De: David Redfern (AU) [mailto:David.Redfern@didata.com.au]
Enviado el: Sabado, 22 de Julio de 2006 06:04 a.m.
Para: Victor Cappuccio; ccielab@groupstudy.com
Asunto: RE: OSPF Null0 DRoute
Yeah tried using the distance command to stop the summary being installed
but even after clearing the routes its still there?
I know it works with bgp. Are you sure it works with eigrp also to stop the
summary to null0 being installed
ip summary-address eigrp 10 130.1.0.0 255.255.0.0 5
router eigrp 10
network 54.1.1.6 0.0.0.0
network 130.1.6.6 0.0.0.0
distance 255 0.0.0.0 255.255.255.255 30
no auto-summary
access-list 30 permit 130.1.0.0 0.0.255.255
Clear ip ro *
D 130.1.0.0/16 is a summary, 00:00:29, Null0
Also tried using a distribute list but it appears I cant stop the eigrp
summary from entering the routing table?
Anyone got any ideas?
Regards,
David Redfern
-----Original Message-----
From: Victor Cappuccio [mailto:cvictor@protokolgroup.com]
Sent: Saturday, 22 July 2006 7:09 PM
To: David Redfern (AU); ccielab@groupstudy.com
Subject: RE: OSPF Null0 DRoute
Hola David.
Did you read my last post?
<quote>
Sorry I forgot to add this:
I know that the ASBR could generate a 0/0 Route to the Ospf Domain, so
packets that comes from route that matches the Null 0 would be converted in
steam, but Saying that the ASBR does not generate the 0 route, has any sence
to keep the Null 0 Route ??
</quote>
Sorry I'm not fluent with English
And to eliminate the discard route in eigrp is by changing the
administrative of the summary to 255, In normal situation we receive the 0/0
route from other Routers and the Null 0 would cause that the route from
others not know in the range of the same supernet would be discarded.
That's ok in this Distance Vector Hibrid Routing Protocol, but it that makes
Sense with OSPF??
-----Mensaje original-----
De: nobody@groupstudy.com [mailto:nobody@groupstudy.com] En nombre de David
Redfern (AU) Enviado el: Sabado, 22 de Julio de 2006 04:17 a.m.
Para: ccielab@groupstudy.com
Asunto: RE: OSPF Null0 DRoute
I believe the side affect is that you are vulnerable to routing loops.
For example you may be following a default route to them, whilst giving them
a summary route to you. If they send traffic to a destination within that
summary that does not exist, you will follow you default back to them. They
will send it back to you via the summary, ect ect.
If you had the route to null0 you will drop any traffic that you receive
that you don't have a longer match for. Hence loop prevention.
Does anyone know a similar command or method to the discard-route
internal/external to use for eigrp to stop the null route from being
installed?
Regards,
David Redfern
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Victor Cappuccio
Sent: Saturday, 22 July 2006 5:06 PM
To: ccielab@groupstudy.com
Subject: OSPF Null0 DRoute
Hi Guys.
Have this question about summarizing external routes in OSPF and the
creation of the null0 to the summary address in the RT.
I know that I could use no discard-route external to avoid the creation of
the Null0 route, but I'm wondering what would be a side affect of this
operation. ?
Has any sense to create a Discard Route from a ASBR connected to other
routing Domain?
Thanks
Victor.-
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