Two things...

1.  You configured a plain-text key on the interface (ip ospf
message-digest-key is what you want)

2.  You CAN have a NULL key with MD5 authentication.  Since you really did
NOT put a key on R5, that's what the router is using

Look at "show ip ospf interface Serial1" and you'll see that ospf
authentication is enabled, but using "key 0" which is the null key.

HTH,

 
Scott Morris, CCIE4 (R&S/ISP-Dial/Security/Service Provider) #4713, JNCIE
#153, CISSP, et al.
CCSI/JNCI-M/JNCI-J
IPexpert VP - Curriculum Development
IPexpert Sr. Technical Instructor
[EMAIL PROTECTED]
http://www.ipexpert.com
 
 

-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Bradley Lowry
Sent: Saturday, March 24, 2007 11:07 AM
To: [email protected]
Subject: [OSL | CCIE_RS] OSPF authentication

R1 and R5 are back to back.  Both run c2500-is-l.123-20.bin, which is
12.3(20), with the IP plus veature set.  My question is this:  If I turn on
MD5 authentication for area 0, and configure a key for S1 on R5, as soon as
I turn on MD5 authentication on R1, the adjacency comes right up even though
R1 doesn't have a key yet.

What am I missing?  Relevant portions of the config are below.

Thanks,
Bradley


R5:
router ospf 100
log-adjacency-changes
area 0 authentication message-digest

interface Serial1
ip address 192.168.10.5 255.255.255.0
ip ospf authentication-key 1 bob
----------------------------------------------------------------

interface Serial1
ip address 192.168.10.2 255.255.255.0
clock rate 56000

r2(config-router)#area 0 authentication message-digest r2(config-router)#
*Mar  1 00:31:29.011: %OSPF-5-ADJCHG: Process 100, Nbr 5.5.5.5 on Serial1
from L OADING to FULL, Loading Done


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