Re: OSPF Distance Command .!

This is wht i got in the end of the day.

R1-----R0------R2 and there is a connection between R1 and R2. So R0 has 2
paths to that segment between R1 and R2.
R1
interface Loopback0
 ip address 100.100.0.100 255.255.255.0
!
interface Loopback1
 ip address 100.100.1.100 255.255.255.0
!
interface Loopback2
 ip address 100.100.2.100 255.255.255.0
!
interface Loopback3
 ip address 100.100.3.100 255.255.255.0
!
interface Serial0/0
 ip address 10.1.1.1 255.255.255.252
 serial restart-delay 0
!
interface Serial0/1
 ip address 20.1.1.1 255.255.255.252
 serial restart-delay 0
!
interface Serial0/2
 no ip address
 shutdown
 serial restart-delay 0
!
interface Serial0/3
 no ip address
 shutdown
 serial restart-delay 0
!
router ospf 1
 router-id 100.100.100.100
 log-adjacency-changes
 network 10.1.1.1 0.0.0.0 area 0
 network 20.1.1.1 0.0.0.0 area 0
 network 100.100.0.100 0.0.0.0 area 0
 network 100.100.1.100 0.0.0.0 area 0
 network 100.100.2.100 0.0.0.0 area 0
 network 100.100.3.100 0.0.0.0 area 0
 distance 90 22.22.22.22 0.0.0.0 SELECT_12.1.1.0_from_R1
!
ip http server
ip forward-protocol nd
!
!
!
!
ip access-list standard ONLY_R1_LOOPBACKS
 permit 1.1.0.0
ip access-list standard SELECT_12.1.1.0_from_R1
 permit 12.1.1.0
ip access-list standard SELECT_12.1.exit
!
!
All router-id Hardcoded. all processes cleared. clear ip route * done.

R0's Routing Table
when R2's ROUTER-ID is lower than R1, A.D of the both the paths gets changed
to the one configured on the Distance command.
R0#sir
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
       D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
       E1 - OSPF external type 1, E2 - OSPF external type 2
       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
       ia - IS-IS inter area, * - candidate default, U - per-user static
route
       o - ODR, P - periodic downloaded static route

Gateway of last resort is not set

     1.0.0.0/24 is subnetted, 1 subnets
O 1.1.0.0 [110/65] via 10.1.1.2, 00:02:07, Serial0/0
     2.0.0.0/24 is subnetted, 1 subnets
O 2.2.0.0 [110/65] via 20.1.1.2, 00:02:07, Serial0/1
     100.0.0.0/24 is subnetted, 4 subnets
C 100.100.0.0 is directly connected, Loopback0
C 100.100.1.0 is directly connected, Loopback1
C 100.100.2.0 is directly connected, Loopback2
C 100.100.3.0 is directly connected, Loopback3
     20.0.0.0/30 is subnetted, 1 subnets
C 20.1.1.0 is directly connected, Serial0/1
     10.0.0.0/30 is subnetted, 1 subnets
C 10.1.1.0 is directly connected, Serial0/0
     12.0.0.0/30 is subnetted, 1 subnets
O 12.1.1.0 [90/128] via 20.1.1.2, 00:02:08, Serial0/1
                 [90/128] via 10.1.1.2, 00:02:08, Serial0/0

When R1's Router-ID is Lower than R2 and R1 hasnt reached the FULL state
with R0. The route thru R2 is shown with A.D of 90(specified in the config.]
R0#sir
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
       D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
       E1 - OSPF external type 1, E2 - OSPF external type 2
       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
       ia - IS-IS inter area, * - candidate default, U - per-user static
route
       o - ODR, P - periodic downloaded static route

Gateway of last resort is not set

     2.0.0.0/24 is subnetted, 1 subnets
O 2.2.0.0 [110/65] via 20.1.1.2, 00:00:09, Serial0/1
     100.0.0.0/24 is subnetted, 4 subnets
C 100.100.0.0 is directly connected, Loopback0
C 100.100.1.0 is directly connected, Loopback1
C 100.100.2.0 is directly connected, Loopback2
C 100.100.3.0 is directly connected, Loopback3
     20.0.0.0/30 is subnetted, 1 subnets
C 20.1.1.0 is directly connected, Serial0/1
     10.0.0.0/30 is subnetted, 1 subnets
C 10.1.1.0 is directly connected, Serial0/0
     12.0.0.0/30 is subnetted, 1 subnets
O 12.1.1.0 [90/128] via 20.1.1.2, 00:00:09, Serial0/1

After R0 -- R1 FULL state
R0#sir
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
       D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
       E1 - OSPF external type 1, E2 - OSPF external type 2
       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
       ia - IS-IS inter area, * - candidate default, U - per-user static
route
       o - ODR, P - periodic downloaded static route

Gateway of last resort is not set

     1.0.0.0/24 is subnetted, 1 subnets
O 1.1.0.0 [110/65] via 10.1.1.2, 00:00:01, Serial0/0
     2.0.0.0/24 is subnetted, 1 subnets
O 2.2.0.0 [110/65] via 20.1.1.2, 00:00:01, Serial0/1
     100.0.0.0/24 is subnetted, 4 subnets
C 100.100.0.0 is directly connected, Loopback0
C 100.100.1.0 is directly connected, Loopback1
C 100.100.2.0 is directly connected, Loopback2
C 100.100.3.0 is directly connected, Loopback3
     20.0.0.0/30 is subnetted, 1 subnets
C 20.1.1.0 is directly connected, Serial0/1
     10.0.0.0/30 is subnetted, 1 subnets
C 10.1.1.0 is directly connected, Serial0/0
     12.0.0.0/30 is subnetted, 1 subnets
O 12.1.1.0 [110/128] via 20.1.1.2, 00:00:02, Serial0/1
                 [110/128] via 10.1.1.2, 00:00:02, Serial0/0

I haven't beeen able to reason why this happens..? but it happens.! and "Say
you have 2 paths to a destination network, then the A.D of the route thru
the Nieghbour with the lowest Router-ID is applied to the other routes thru
different nieghbors or paths" I have no idea why..!

any ideas?

when R
Thanking You

Yours Sincerely

Divin Mathew John
divinjohn_at_gmail.com
divin_at_dide3d.com
http://www.dide3d.com
+91 9945430983
+91 9846697191
+974 5008916
PGP PUBLIC KEY BLOCK @ http://www.dide3d.com/divin_Public_PGP_key.txt
Sent from Bangalore, KA, India

On Fri, May 22, 2009 at 5:52 AM, Chris Breece <cbreece1_at_gmail.com> wrote:

> Hey Divin,
>
> I ran into this same thing on Wednesday. I tried to use the distance
> command in the same fashion. I wanted to prefer some routes to go to one
> neighbor instead of another. I got the same results as you show below. If
> there was another available next-hop, it changed the AD for both paths.
>
> I ended up doing "distance 255 1.1.1.1 0.0.0.0 Named_ACL". This effectively
> deleted one of the routes out of my routing table. In that scenario, I lost
> my redundant route... but it seemed to fit the requirements.
>
> I don't know that its a bug, but I can confirm another human being saw the
> same issue you did :P
>
> Chris
>
>
>
>
>
> On Thu, May 21, 2009 at 4:13 PM, Divin Mathew John <divinjohn_at_gmail.com>wrote:
>
>> I have this problem. i am trying to change the A.D of a particular path in
>> OSPF using distance command. My config is pasted below.
>> Topology
>>
>> R0
>> interface Loopback0
>> ip address 100.100.0.100 255.255.255.0
>> !
>> interface Loopback1
>> ip address 100.100.1.100 255.255.255.0
>> !
>> interface Loopback2
>> ip address 100.100.2.100 255.255.255.0
>> !
>> interface Loopback3
>> ip address 100.100.3.100 255.255.255.0
>> !
>> interface Serial0/0
>> ip address 10.1.1.1 255.255.255.252
>> serial restart-delay 0
>> !
>> interface Serial0/1
>> ip address 20.1.1.1 255.255.255.252
>> serial restart-delay 0
>> !
>>
>> router ospf 1
>> log-adjacency-changes
>> network 10.1.1.1 0.0.0.0 area 0
>> network 20.1.1.1 0.0.0.0 area 0
>> network 100.100.0.100 0.0.0.0 area 0
>> network 100.100.1.100 0.0.0.0 area 0
>> network 100.100.2.100 0.0.0.0 area 0
>> network 100.100.3.100 0.0.0.0 area 0
>> distance 90 12.1.1.1 0.0.0.0 SELECT_12.1.1.0_from_R1
>> !
>> ip access-list standard SELECT_12.1.1.0_from_R1
>> permit 12.1.1.0
>>
>> R0#show ip ospf neighbor
>>
>> Neighbor ID Pri State Dead Time Address
>> Interface
>> 20.1.1.2 0 FULL/ - 00:00:37 20.1.1.2
>> Serial0/1
>> 12.1.1.1 0 FULL/ - 00:00:33 10.1.1.2
>> Serial0/0
>>
>> R0#sir
>> Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
>> D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
>> N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
>> E1 - OSPF external type 1, E2 - OSPF external type 2
>> i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS
>> level-2
>> ia - IS-IS inter area, * - candidate default, U - per-user static
>> route
>> o - ODR, P - periodic downloaded static route
>>
>> Gateway of last resort is not set
>>
>> 1.0.0.0/24 is subnetted, 1 subnets
>> O 1.1.0.0 [110/65] via 10.1.1.2, 00:01:35, Serial0/0
>> 2.0.0.0/32 is subnetted, 1 subnets
>> O 2.2.0.2 [110/65] via 20.1.1.2, 00:01:35, Serial0/1
>> 100.0.0.0/24 is subnetted, 4 subnets
>> C 100.100.0.0 is directly connected, Loopback0
>> C 100.100.1.0 is directly connected, Loopback1
>> C 100.100.2.0 is directly connected, Loopback2
>> C 100.100.3.0 is directly connected, Loopback3
>> 20.0.0.0/30 is subnetted, 1 subnets
>> C 20.1.1.0 is directly connected, Serial0/1
>> 10.0.0.0/30 is subnetted, 1 subnets
>> C 10.1.1.0 is directly connected, Serial0/0
>> * 12.0.0.0/30 is subnetted, 1 subnets
>> O 12.1.1.0 [90/128] via 20.1.1.2, 00:01:36, Serial0/1
>> [90/128] via 10.1.1.2, 00:01:36, Serial0/0*
>>
>> according to my distance command only the route from R1 should have
>> changed
>> its A.D. but here even though i specified the ROUTER-ID of the router
>> whose
>> path i need to change the A.D it doesn't change that... it changes the A.D
>> of all paths to the destination..! is this a BUG?
>>
>>
>> Thanking You
>>
>> Yours Sincerely
>>
>> Divin Mathew John
>> divinjohn_at_gmail.com
>> divin_at_dide3d.com
>> http://www.dide3d.com
>> +91 9945430983
>> +91 9846697191
>> +974 5008916
>> PGP PUBLIC KEY BLOCK @ http://www.dide3d.com/divin_Public_PGP_key.txt
>> Sent from Bangalore, KA, India
>>
>>
>> Blogs and organic groups at http://www.ccie.net
>>
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Received on Fri May 22 2009 - 06:12:07 ART