RE: OSPF Authentication and Virtual Links

From: Patrick McKinnis (pmckinni@xxxxxxxxx)
Date: Mon Feb 28 2000 - 21:18:03 GMT-3


   
   
   Joel's right. I got it up without a hitch. Here are my configs.
   
   HUB (Backbone/Area 0) Router:
   
   router ospf 100
    network 172.16.100.0 0.0.0.255 area 0
    network 172.16.200.0 0.0.0.255 area 10
    network 13.0.0.0 0.255.255.255 area 0
    area 10 virtual-link 172.16.200.2 message-digest-key 1 md5 sanfran
   
   SPOKE (Area 10/5) Router:
   
   router ospf 100
    area 10 virtual-link 172.16.200.1 message-digest-key 1 md5 sanfran
    redistribute rip metric-type 1 subnets
    network 172.16.200.0 0.0.0.255 area 10
    network 180.180.180.0 0.0.0.255 area 5
   
   I have Area 0 on the HUB Router, and Area 10 on the serial link
   between HUB and SPOKE. A loopback in Area 5 on SPOKE is
   virtual-linked across Area 10 to Area 0. As you can see, I have MD5
   authentication enabled and working. Here's HUB Router's routing
   table:
   
   r1#sh ip route
   Codes: C - connected, S - static, I - IGRP, 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, E - EGP
          i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, * -
   candidate default
          U - per-user static route, o - ODR
   
   Gateway of last resort is not set
   
        180.180.0.0/32 is subnetted, 1 subnets
   O IA 180.180.180.180 [110/65] via 172.16.200.2, 00:06:12, Serial0.2
        144.144.0.0/24 is subnetted, 1 subnets
   O E1 144.144.144.0 [110/84] via 172.16.200.2, 00:06:12, Serial0.2
   C 13.0.0.0/8 is directly connected, BRI0
        172.16.0.0/24 is subnetted, 3 subnets
   C 172.16.200.0 is directly connected, Serial0.2
   O 172.16.25.0 [110/128] via 172.16.100.2, 00:06:12, Serial0.1
   C 172.16.100.0 is directly connected, Serial0.1
   
   The presence of 180.180.180.180/32 is the money route. Notice it's a
   host-specific route. OSPF treats loopbacks as stub areas and reflects
   that with the 32-bit subnet mask.
   
   Hope this helps.
   
   Patrick
   
   
   -----Original Message-----
   From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
   Joel A. Cochran
   Sent: Monday, February 28, 2000 5:01 PM
   To: Richard Wagner; ccielab@groupstudy.com
   Subject: Re: OSPF Authentication and Virtual Links
   
   Richard,
   
       Keep in mind that the virtual link is a logical connection to area
   0. Although you have not put any interfaces on the router with the
   virtual link into area 0, the virtual link is considered an interface
   in area 0.
   
   
   
   Easy fix:
   
       On the router not connected to area 0:
   
       router ospf xx
   
       area 0 authentication {message-digest} if using md5.
   
   
   
   Set it up just as if you were on area 0... you just dont have the
   interface commands.
   
   I've tried it, and this works.
   
   
   
   Joel Cochran, CCIE# 5448.
   
   
   
   
   
   ----- Original Message -----
   
   From: Richard Wagner
   
   To: 'ccielab@groupstudy.com'
   
   Sent: Monday, February 28, 2000 4:28 PM
   
   Subject: OSPF Authentication and Virtual Links
   
     When configuring OSPF with multiple areas, I tried implementing md5
     authentication in Area0.
     I had the whole mess working without the authentication, and the
     the virtual
     link was working fine.
     When I enable authentication in Area0, the virtual link no longer
     worked.
     I pounded on it for a while and just couldn't make it work. I
     tried a few
     things with no success:
     -applying authentication parameters on the virtual-link statements
     (seemed
     reasonable)
     -applying md5 authentication to all areas and interfaces
     *everywhere* on
     *every* router (shotgun approach)
     (I was hoping that those desparate measures would yield a working
     config
     where I could remove things one-by-one to determine what was really
     necessary)
     The debugs would show (I'm recalling this while at work)...
     "expected type
     2, got type 0 for ospf authentication" or something like that
     (sorry for not
     being exact).
     In the end, I removed all authentication statements and the world
     worked
     again.
     There's a "stunt" here... does anybody know what it is?
     Thanks for your help everybody!
     Richard



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