BIRD - iBGP between both RS - invalid NEXT-HOP notification.

Javor Kliachev jkliachev at neterra.net
Thu Mar 20 15:14:11 CET 2014


Hello,

Thanks for your advice but I think that you misunderstood our issue.

We have established iBGP session between two route servers with IP 
address in same ethernet broadcast domain.

RS1 - 10.1.0.100/24
|
iBGP
|
RS2 - 10.1.0.200/24

Each prefix is learned correctly in both RS.

31.13.244.0/24     via 10.1.0.252 on eth0 [R0_252 14:44] * (100) [AS60230i]
                              via 10.1.0.252 on eth0 [*R0_100* 15:12 
from 10.1.0.100] (100) [AS60230i]

All members in the IXP have assigned IP address from 10.1.0.0/24. The 
traffic should not goes to both RS.
They're used only to hold the BGP sessions to the members.

I just think that this message is rather a cosmetic issue then real 
problem but I'm not sure.

Thanks again.

Best~

On 03/20/2014 11:49 AM, Frédéric LOUI wrote:
> Hi Javor,
>
> I do not have the whole set-up context therefore my interpretation 
> might be might be wrong.
>
> When you active (i)BGP between 2 BGP speakers. You should make sure that:
>
> 1) Either all point to point links connected ([/30 | /31] for IPv4) to 
> each (i)BGP speaker can be reachable by both system
>     * via static
>     * or a routing protocol such as OSPF (use the passive interface knob)
>
> 2) Either by using NEXT-HOP-SELF in your iBGP session between RS1 and 
> RS2 (and vice versa)
>
> So this will guarantee that your BGP NEXT HOP is reachable and that 
> might clear your INVALID NEXT HOP issue.
>
> Hope this help.
> — Frédéric
>
> Le 20 mars 2014 à 10:20, Javor Kliachev <jkliachev at neterra.net 
> <mailto:jkliachev at neterra.net>> a écrit :
>
>> Hello,
>>
>> Unfortunately, I still have no response from anybody. The messages 
>> continue to come into our logs.
>> The iBGP session is UP since more than 1 week and till this moment we 
>> don't have complaints by some member.
>>
>> But this messages are definitely strange and we would be happy if 
>> someone may give some advice according to
>> their experience.
>>
>> For any questions or need more information & debug, please feel free 
>> to contact me at anytime.
>>
>> I really highly appreciate any help.
>>
>> Thanks in advance.
>>
>> Best~
>>
>> On 03/07/2014 03:35 PM, Javor Kliachev wrote:
>>> Hello,
>>>
>>> We use BIRD as route server for a long time without any problems. We 
>>> have both fully symmetric RS for redundancy.
>>>
>>> Yesterday we decided to establish "internal BGP session" between 
>>> both of them. The reason to do this is to achieve prefix symmetric 
>>> on both RS. Some of our members hold BGP session only with one of 
>>> our route servers.
>>>
>>> But after establishing this BGP session we began to see the 
>>> following message into our logs on both RS for total random prefixes 
>>> on absolutely random intervals.
>>>
>>> Here is part of my bird.log:
>>> 07-03-2014 14:19:41 R0_29: Invalid NEXT_HOP attribute in route 
>>> 178.254.232.0/21
>>> 07-03-2014 14:19:41 R0_30: Invalid NEXT_HOP attribute in route 
>>> 178.254.232.0/21
>>> 07-03-2014 14:18:52 R0_52: Invalid NEXT_HOP attribute in route 
>>> 79.140.156.0/22
>>> 07-03-2014 14:18:52 R0_52: Invalid NEXT_HOP attribute in route 
>>> 79.140.148.0/22
>>> 07-03-2014 14:18:52 R0_52: Invalid NEXT_HOP attribute in route 
>>> 79.140.144.0/20
>>> 07-03-2014 14:18:52 R0_52: Invalid NEXT_HOP attribute in route 
>>> 79.140.152.0/22
>>> 07-03-2014 14:18:52 R0_52: Invalid NEXT_HOP attribute in route 
>>> 79.140.144.0/22
>>> 07-03-2014 14:18:52 R0_52: Invalid NEXT_HOP attribute in route 
>>> 79.140.156.0/22
>>> 07-03-2014 14:18:52 R0_52: Invalid NEXT_HOP attribute in route 
>>> 79.140.144.0/20
>>> 07-03-2014 14:18:52 R0_52: Invalid NEXT_HOP attribute in route 
>>> 79.140.148.0/22
>>> 07-03-2014 14:18:52 R0_52: Invalid NEXT_HOP attribute in route 
>>> 79.140.152.0/22
>>> 07-03-2014 14:18:52 R0_52: Invalid NEXT_HOP attribute in route 
>>> 79.140.144.0/22
>>> 07-03-2014 14:16:39 R0_29: Invalid NEXT_HOP attribute in route 
>>> 178.254.232.0/21
>>> 07-03-2014 14:16:39 R0_30: Invalid NEXT_HOP attribute in route 
>>> 178.254.232.0/21
>>> 07-03-2014 14:01:39 R0_52: Invalid NEXT_HOP attribute in route 
>>> 95.168.66.0/23
>>> 07-03-2014 14:01:39 R0_52: Invalid NEXT_HOP attribute in route 
>>> 95.168.68.0/23
>>> 07-03-2014 13:52:02 R0_14: Invalid NEXT_HOP attribute in route 
>>> 151.252.198.0/24
>>> 07-03-2014 13:51:57 R0_14: Invalid NEXT_HOP attribute in route 
>>> 151.252.198.0/24
>>> 07-03-2014 13:29:36 R0_87: Invalid NEXT_HOP attribute in route 
>>> 85.11.144.0/20
>>> 07-03-2014 13:29:28 R0_87: Invalid NEXT_HOP attribute in route 
>>> 85.11.144.0/20
>>> 07-03-2014 13:29:15 R0_87: Invalid NEXT_HOP attribute in route 
>>> 85.11.144.0/20
>>> 07-03-2014 13:29:06 R0_87: Invalid NEXT_HOP attribute in route 
>>> 85.11.144.0/20
>>> 07-03-2014 13:28:14 R0_87: Invalid NEXT_HOP attribute in route 
>>> 85.187.120.0/22
>>> 07-03-2014 13:28:14 R0_87: Invalid NEXT_HOP attribute in route 
>>> 85.187.120.0/22
>>> 07-03-2014 13:19:36 R0_87: Invalid NEXT_HOP attribute in route 
>>> 85.187.120.0/22
>>> 07-03-2014 13:19:31 R0_87: Invalid NEXT_HOP attribute in route 
>>> 85.187.120.0/22
>>> 07-03-2014 13:19:31 R0_87: Invalid NEXT_HOP attribute in route 
>>> 85.11.144.0/20
>>> 07-03-2014 13:19:31 R0_87: Invalid NEXT_HOP attribute in route 
>>> 85.187.120.0/22
>>> 07-03-2014 13:19:22 R0_87: Invalid NEXT_HOP attribute in route 
>>> 85.11.144.0/20
>>> 07-03-2014 13:13:43 R0_71: Invalid NEXT_HOP attribute in route 
>>> 46.229.194.0/24
>>> 07-03-2014 13:13:43 R0_71: Invalid NEXT_HOP attribute in route 
>>> 46.229.192.0/23
>>> 07-03-2014 13:13:42 R0_29: Invalid NEXT_HOP attribute in route 
>>> 46.229.194.0/24
>>> 07-03-2014 13:13:42 R0_29: Invalid NEXT_HOP attribute in route 
>>> 46.229.192.0/23
>>> 07-03-2014 13:06:22 R0_60: Invalid NEXT_HOP attribute in route 
>>> 193.104.73.0/24
>>> 07-03-2014 13:03:54 R0_52: Invalid NEXT_HOP attribute in route 
>>> 178.79.61.0/24
>>> 07-03-2014 12:54:56 R0_60: Invalid NEXT_HOP attribute in route 
>>> 89.35.114.0/24
>>> 07-03-2014 12:54:56 R0_60: Invalid NEXT_HOP attribute in route 
>>> 86.105.150.0/24
>>> 07-03-2014 12:54:56 R0_60: Invalid NEXT_HOP attribute in route 
>>> 46.102.181.0/24
>>> 07-03-2014 12:54:56 R0_60: Invalid NEXT_HOP attribute in route 
>>> 46.102.176.0/24
>>> 07-03-2014 12:54:56 R0_60: Invalid NEXT_HOP attribute in route 
>>> 37.156.69.0/24
>>> 07-03-2014 12:54:25 R0_60: Invalid NEXT_HOP attribute in route 
>>> 188.240.70.0/24
>>> 07-03-2014 12:54:25 R0_60: Invalid NEXT_HOP attribute in route 
>>> 188.212.157.0/24
>>> 07-03-2014 12:34:43 R0_52: Invalid NEXT_HOP attribute in route 
>>> 91.148.106.0/24
>>> 07-03-2014 12:27:48 R0_52: Invalid NEXT_HOP attribute in route 
>>> 91.148.118.0/24
>>> 07-03-2014 12:16:33 R0_29: Invalid NEXT_HOP attribute in route 
>>> 178.254.232.0/21
>>> 07-03-2014 12:16:33 R0_30: Invalid NEXT_HOP attribute in route 
>>> 178.254.232.0/21
>>> 07-03-2014 12:09:39 R0_87: Invalid NEXT_HOP attribute in route 
>>> 85.11.144.0/20
>>> 07-03-2014 12:09:10 R0_87: Invalid NEXT_HOP attribute in route 
>>> 85.11.144.0/20
>>> 07-03-2014 12:08:57 R0_87: Invalid NEXT_HOP attribute in route 
>>> 85.187.120.0/22
>>> 07-03-2014 12:08:50 R0_87: Invalid NEXT_HOP attribute in route 
>>> 85.187.120.0/22
>>> 07-03-2014 12:08:49 R0_87: Invalid NEXT_HOP attribute in route 
>>> 85.187.120.0/22
>>> 07-03-2014 12:02:41 R0_52: Invalid NEXT_HOP attribute in route 
>>> 212.200.0.0/21
>>> 07-03-2014 11:47:01 R0_29: Invalid NEXT_HOP attribute in route 
>>> 178.254.232.0/21
>>> 07-03-2014 11:47:01 R0_30: Invalid NEXT_HOP attribute in route 
>>> 178.254.232.0/21
>>> 07-03-2014 10:55:50 R0_60: Invalid NEXT_HOP attribute in route 
>>> 91.206.209.0/24
>>>
>>> I had checked many times and make many tests if the next-hop is 
>>> correct and everything looks
>>> fine but this messages  comes permanently :)
>>>
>>> We managed to troubleshoot the following behavior and relationship 
>>> and see the following effect:
>>>
>>> Our scenario:
>>>
>>> 0.100                 0.200
>>> RS1 <- iBGP -> RS2
>>>   |                       |
>>>   |                       |
>>> TEST.AS -----------
>>> 0.252
>>>
>>> TEST.AS announce: 31.13.244.0/24
>>>
>>> RS2 learn this prefix as:
>>>
>>> 31.13.244.0/24     via 10.1.0.252 on eth0 [R0_252 14:44] * (100) 
>>> [AS60230i]
>>>                              via 10.1.0.252 on eth0 [*R0_100* 15:12 
>>> from 10.1.0.100] (100) [AS60230i]
>>>
>>>
>>> As soon as we stop to announce 31.13.244.0/24 from TEST.AS to RS1, 
>>> in the logs of RS1 begin to come the following message:
>>>
>>> 07-03-2014 15:10:09R0_252: Invalid NEXT_HOP attribute in route 
>>> 31.13.244.0/24
>>>
>>> But when we try to shutdown (administratively ) the session between 
>>> TEST.AS and RS1 this behavior does not occur and everything seems 
>>> normal.
>>>
>>> I hope this information will be useful for resolving this strange issue.
>>>
>>> Here is our configuration set on both RS. The real AS number & IPs 
>>> has been changed for security reason :)
>>>
>>> # RS2:
>>> table T65535
>>>
>>> protocol pipe P65535 from iBGP_PIPES {
>>>   description "RS1";
>>>   peer table T65535;
>>>   export where RS_PIPE_OUT();
>>> }
>>>
>>> protocol bgp R0_100 from iBGP {
>>>   description "0.100_iBGP_RS1";
>>>   source address 10.1.0.200;
>>>   neighbor 10.1.0.100 as 65535;
>>>   import all;
>>>   export all;
>>>   passive off;
>>>   table T65535;
>>>   route limit 10000;
>>>   gateway direct;
>>> }
>>>
>>>
>>> # RS1:
>>> table T65535
>>>
>>> protocol pipe P65535 from iBGP_PIPES {
>>>   description "RS2";
>>>   peer table T65535;
>>>   export where RS_PIPE_OUT();
>>> }
>>>
>>> protocol bgp R0_200 from iBGP {
>>>   description "0.200_iBGP_RS1";
>>>   source address 10.1.0.100;
>>>   neighbor 10.1.0.200 as 65535;
>>>   import all;
>>>   export all;
>>>   passive off;
>>>   table T65535;
>>>   route limit 10000;
>>>   gateway direct;
>>> }
>>>
>>> # show bgp summary shows the following:
>>> # RS2:
>>> ---------------------------------------------------------------- adv 
>>> / rcv / limit ---
>>> 0.100_iBGP_RS1    10.1.0.100    65535    Mar06 Established    
>>> 4527/3235/10000
>>> --------------------------------------------------------------------------------------
>>>
>>> # RS1:
>>> ---------------------------------------------------------------- adv 
>>> / rcv / limit ---
>>> 0.200_iBGP_RS2    10.1.0.200    65535    Mar06 Established    
>>> 3235/4527/10000
>>> --------------------------------------------------------------------------------------
>>>
>>> Any ideas or thoughts are highly appreciated!
>>>
>>> Thanks in advance!
>>>
>>> -- 
>>> ---
>>> Find out about our new Cloud service - Cloudware.bg 
>>> <http://cloudware.bg/?utm_source=email&utm_medium=signature&utm_content=link&utm_campaign=newwebsite>
>>> Access anywhere. Manage it yourself. Pay as you go.
>>> ------------------------------------------------------------------------
>>> *Javor Kliachev*
>>> IP Engineer
>>>
>>> Neterra Ltd.
>>> Telephone: +359 2 975 16 16
>>> Fax: +359 2 975 34 36
>>> www.neterra.net <http://www.neterra.net/>
>>>
>>>
>>
>> -- 
>> ---
>> Find out about our new Cloud service - Cloudware.bg 
>> <http://cloudware.bg/?utm_source=email&utm_medium=signature&utm_content=link&utm_campaign=newwebsite>
>> Access anywhere. Manage it yourself. Pay as you go.
>> ------------------------------------------------------------------------
>> *Javor Kliachev*
>> IP Engineer
>>
>> Neterra Ltd.
>> Telephone: +359 2 975 16 16
>> Fax: +359 2 975 34 36
>> www.neterra.net <http://www.neterra.net/>
>>
>>
>

-- 
---
Find out about our new Cloud service - Cloudware.bg 
<http://cloudware.bg/?utm_source=email&utm_medium=signature&utm_content=link&utm_campaign=newwebsite>
Access anywhere. Manage it yourself. Pay as you go.
------------------------------------------------------------------------
*Javor Kliachev*
IP Engineer

Neterra Ltd.
Telephone: +359 2 975 16 16
Fax: +359 2 975 34 36
www.neterra.net <http://www.neterra.net>


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