RE: OSPF authentication using rollover keys

From: Scott Morris (swm@emanon.com)
Date: Sat May 27 2006 - 15:03:10 ART


Do you have any neighbor using the other key??? If you do, then they'll
all show up:

Emanon-R1(config)#do sh ip o n

Neighbor ID Pri State Dead Time Address Interface
15.15.15.15 0 FULL/DROTHER 00:01:48 172.17.150.3
Serial0/0.1
200.103.1.1 0 FULL/DROTHER 00:01:39 172.17.150.2
Serial0/0.1
172.17.155.5 0 FULL/ - 00:00:33 172.17.155.5 Serial0/1
Emanon-R1(config)#do sh ip o i s0/0.1
Serial0/0.1 is up, line protocol is up
  Internet Address 172.17.150.1/24, Area 0
  Process ID 1, Router ID 24.24.24.24, Network Type NON_BROADCAST, Cost: 64
  Transmit Delay is 1 sec, State DR, Priority 128
  Designated Router (ID) 24.24.24.24, Interface address 172.17.150.1
  No backup designated router on this network
  Timer intervals configured, Hello 30, Dead 120, Wait 120, Retransmit 5
    oob-resync timeout 120
    Hello due in 00:00:16
  Index 1/3, flood queue length 0
  Next 0x0(0)/0x0(0)
  Last flood scan length is 5, maximum is 6
  Last flood scan time is 8 msec, maximum is 12 msec
  Neighbor Count is 2, Adjacent neighbor count is 2
    Adjacent with neighbor 15.15.15.15
    Adjacent with neighbor 200.103.1.1
  Suppress hello for 0 neighbor(s)
  Message digest authentication enabled
    Youngest key id is 3
    Rollover in progress, 1 neighbor(s) using the old key(s):
      key id 1
      key id 2
Emanon-R1(config)#do sh run int s0/0.1
Building configuration...

Current configuration : 505 bytes
!
interface Serial0/0.1 multipoint
 ip address 172.17.150.1 255.255.255.0
 ip router isis
 ip pim sparse-dense-mode
 service-policy input testing
 ip ospf authentication message-digest
 ip ospf message-digest-key 1 md5 IPExpert
 ip ospf message-digest-key 2 md5 R2Key
 ip ospf message-digest-key 3 md5 R3Key
 ip ospf priority 128
 isis priority 127
 frame-relay class trfshape
 frame-relay map ip 172.17.150.2 102 broadcast
 frame-relay map ip 172.17.150.3 103 broadcast
 no frame-relay inverse-arp
end

Emanon-R1(config)#

Note, my hub there actually has three keys configured on it. Although
according to the show ip ospf interface command, only two of them are used.
Because I have two peers using separate/different keys.

HTH,

 
Scott Morris, CCIE4 (R&S/ISP-Dial/Security/Service Provider) #4713, JNCIE
#153, CISSP, et al.
CCSI/JNCI
IPExpert CCIE Program Manager
IPExpert Sr. Technical Instructor
smorris@ipexpert.com
http://www.ipexpert.com
 
 

-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Larry Chuon
Sent: Friday, May 26, 2006 11:19 AM
To: Cisco certification
Subject: OSPF authentication using rollover keys

Hi group,

I've three routers. Each is configured to do md5 authentication. I put in
key 1. Everything works fine. Then, I proceed to add a second key on R1
(hub) and R3.

R1:
 ip ospf authentication message-digest
 ip ospf message-digest-key 1 md5 cisco
 ip ospf message-digest-key 2 md5 cisco2

R3:
ip ospf authentication message-digest
ip ospf message-digest-key 2 md5 cisco2

Now, only R1 and R3 form adjacency.

R2 display an error message:

*May 26 15:21:29.575: OSPF: Send with youngest Key 1 !
Serial0/0/0 : Mismatch Authentication Key - No message digest key 2 on
interface

It can't form adjacency with the hub.

Both R1 and R3 has the following info AFTER a reboot. I believe that all
three routers were working fine before the reboot.

sh ip os int s0/0/0 | in auth|key
  Message digest authentication enabled
    Youngest key id is 2

What is the proper way to do rollover?

TIA,
Larry



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