[quagga-users 13108] Re: avoid interfaces

Alexis Rosen quagga-users at alexis.users.panix.com
Fri Dec 21 08:17:01 GMT 2012


This does seem like correct behavior to me. It's just an unfortunate consequence of VRRP/OSPF interaction.

Try this workaround:

1) Put a /24 address on eth0, in the /24 you want to use, but not the actual IP you want to use for OSPF
2) Put a /32 on eth0 as an alias, which is inside the /24, and not the same as the /32 on the VRRP interface.

Now, in OSPF, if you designate the /32 alias in your network statement instead of the /24, it should bring OSPF up on eth0, without coming up on the VRRP interface.

If that doesn't work, you could always configure OSPF on the vrrp interface in such a way as to prevent the adjacency from ever coming up. Or even just block all OSPF packets coming to the VRRP interface using the packet filter.

/a

On Dec 21, 2012, at 2:12 AM, Mattias Walström wrote:
> Is this behaviour by-design? If so, I will need to patch zebra to remove the interface.
> 
> Mattias
> 
> On 2012-12-19 01:00, Mattias Walström wrote:
>> Thanks for all answers, now I feel that I have a little better understanding about what is happening.
>> 
>> I tested with the /32 in the network command, but it did not work, OSPF did not get enabled on eth0, and according to the documentation it shouldn't either.
>> 
>> now to the part I can not understand, if I run the following test:
>> 
>> to emulate the VRRP interface I added a /32 address to loopback.
>> ip addr add 192.168.0.99/32 dev lo
>> 
>> eth0: 192.168.0.1/24
>> router ospf
>>  network 192.168.0.0/24 area 0.0.0.0
>> 
>> R1> show ip ospf route
>> ============ OSPF network routing table ============
>> N    192.168.0.0/24        [10] area: 0.0.0.0
>>                            directly attached to eth0
>> N    192.168.0.99/32       [10] area: 0.0.0.0
>>                            directly attached to lo
>> 
>> ============ OSPF router routing table =============
>> 
>> ============ OSPF external routing table ===========
>> 
>> eth1: 192.168.0.91/24
>> router ospf
>>  network 192.168.0.0/24 area 0.0.0.0
>> 
>> R2> show ip ospf route
>> ============ OSPF network routing table ============
>> N    192.168.0.0/24        [10] area: 0.0.0.0
>>                            directly attached to eth1
>> N    192.168.0.99/32       [20] area: 0.0.0.0
>>                            via 192.168.0.1, eth1
>> 
>> ============ OSPF router routing table =============
>> 
>> ============ OSPF external routing table ===========
>> 
>> As stated above, I do not use any redistribute command, just the network command.
>> 
>> If I do network 192.168.0.0/24, why is the /32 get announced? Shouldn't it be announced as a /24 if that is what I have said in the network command? I can not find an explanation for this in the documentation, it really puzzles me.
>> 
>> This is why I want to remove the VRRP interface from zebra/OSPF, but maybe that is the wrong approach?



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