Always working on my problem, if anybody can help me.... please.
Here's a tcpdump of BGP exchanges between the neighbor (192.168.53.118)
and me (192.168.53.113) :
_Open from my neighbor, no 4 Byte AS capability :_
17:26:04.529327 IP (tos 0xc0, ttl 1, id 16154, offset 0, flags [DF],
proto TCP (6), length 79)
192.168.53.113.44169 > 192.168.53.118.bgp: Flags [P.], cksum 0x6e87
(correct), seq 687533061:687533100, ack 2368601536, win 16384, length
39: BGP, length: 39
Open Message (1), length: 39
Version 4, my AS 65426, Holdtime 20s, ID 46.226.128.1
Optional parameters, length: 10
Option Capabilities Advertisement (2), length: 8
Multiprotocol Extensions (1), length: 4
AFI IPv4 (1), SAFI Unicast (1)
0x0000: 0001 0001
_Open from me, 4 Byte AS capability :_
17:26:04.530298 IP (tos 0xc0, ttl 1, id 61896, offset 0, flags [DF],
proto TCP (6), length 93)
192.168.53.118.bgp > 192.168.53.113.44169: Flags [P.], cksum 0x7ecf
(correct), seq 1:54, ack 39, win 16345, length 53: BGP, length: 53
Open Message (1), length: 53
Version 4, my AS 35330, Holdtime 180s, ID 192.168.53.118
Optional parameters, length: 24
Option Capabilities Advertisement (2), length: 6
Multiprotocol Extensions (1), length: 4
AFI IPv4 (1), SAFI Unicast (1)
0x0000: 0001 0001
Option Capabilities Advertisement (2), length: 2
Route Refresh (Cisco) (128), length: 0
Option Capabilities Advertisement (2), length: 2
Route Refresh (2), length: 0
Option Capabilities Advertisement (2), length: 6
* 32-Bit AS Number (65), length: 4**
** 4 Byte AS 35330*
0x0000: 0000 8a02
_Keepalives..._
17:26:04.530350 IP (tos 0xc0, ttl 1, id 61897, offset 0, flags [DF],
proto TCP (6), length 59)
192.168.53.118.bgp > 192.168.53.113.44169: Flags [P.], cksum 0x320e
(correct), seq 54:73, ack 39, win 16345, length 19: BGP, length: 19
Keepalive Message (4), length: 19
17:26:04.530479 IP (tos 0xc0, ttl 1, id 28050, offset 0, flags [DF],
proto TCP (6), length 59)
192.168.53.113.44169 > 192.168.53.118.bgp: Flags [P.], cksum 0x31e7
(correct), seq 39:58, ack 73, win 16365, length 19: BGP, length: 19
Keepalive Message (4), length: 19
_Update :_
17:26:04.530926 IP (tos 0xc0, ttl 1, id 37630, offset 0, flags [DF],
proto TCP (6), length 94)
192.168.53.113.44169 > 192.168.53.118.bgp: Flags [P.], cksum 0x4a46
(correct), seq 58:112, ack 73, win 16384, length 54: BGP, length: 54
Update Message (2), length: 54
Origin (1), length: 1, Flags [T]: IGP
0x0000: 00
* AS Path (2), length: 4, Flags [T]: 23456 *
0x0000: 0201 5ba0
Next Hop (3), length: 4, Flags [T]: 192.168.53.113
0x0000: c0a8 3571
* AS4 Path (17), length: 6, Flags [OT]: <4 byte AS>*
0x0000: 0201 0003 039c
Updated routes:
<net>/21
_Error notification :_
17:26:04.531860 IP (tos 0xc0, ttl 1, id 61899, offset 0, flags [DF],
proto TCP (6), length 68)
192.168.53.118.bgp > 192.168.53.113.44169: Flags [P.], cksum 0xc800
(correct), seq 73:101, ack 112, win 16272, length 28: BGP, length: 28
* Notification Message (3), length: 28, UPDATE Message Error (3),
subcode Malformed AS_PATH (11)*
Regards,
Cédric
Le 30/07/2013 13:54, OCEANET - Cédric BASSAGET a écrit :
> So is my problem a configuration issue, a problem in openbgpd or just
> something that is undoable ?
> Regards,
> Cédric
>
> Le 30/07/2013 09:01, OCEANET - Cédric BASSAGET a écrit :
>> Hello Claudio,
>>
>> I'm using AS 65426.
>>
>> This is the UPDATE message my bgpd sends to my neighbor :
>>
>> Update Message (2), length: 54
>> Origin (1), length: 1, Flags [T]: IGP
>> 0x0000: 00
>> AS Path (2), length: 4, Flags [T]: 23456
>> 0x0000: 0201 5ba0
>> Next Hop (3), length: 4, Flags [T]: 192.168.53.113
>> 0x0000: c0a8 3571
>> AS4 Path (17), length: 6, Flags [OT]: <4 bytes AS>
>> 0x0000: 0201 0003 039c
>> Updated routes:
>> 46.226.x.x/21
>>
>>
>> Regards,
>> Cédric
>>
>> Le 29/07/2013 23:37, Claudio Jeker a écrit :
>>> On Mon, Jul 29, 2013 at 09:33:55AM +0200, OCEANET - Cédric BASSAGET wrote:
>>>> Hello,
>>>>
>>>> I'm trying to replace two cisco routers by two openBGPd routers.
>>>> A have 3 neighbors, two with 4-bytes AS, and one which only supports
>>>> 2-bytes AS for now.
>>>> I have a 4-bytes AS too.
>>>>
>>>> So in my bgpd.conf, I have :
>>>>
>>>> ...
>>>> AS <my 4bytes> <a 2bytes AS>
>>>> network z.z.z.z/21
>>>> ...
>>>> neighbor <neighbor's ip address> #a neighbor which supports 4 bytes AS
>>>> {
>>>> remote-as <neighbor's AS>
>>>> set prepend-self 1
>>>> }
>>>> ...
>>>> neighbor <neighbor's ip address> #a neighbor which supports 2 bytes
>>>> AS only
>>>> {
>>>> remote-as <neighbor's AS>
>>>> set prepend-self 2
>>>> }
>>>> ...
>>>>
>>>> My problem is that my second neighbor return this message :
>>>>
>>>> neighbor : received notification: error in UPDATE message, AS-Path
>>>> unacceptable
>>>>
>>>> I think bgpd is trying to prepend the neighbor which does not support
>>>> 4bytes AS with... a 4 bytes AS, due to the "set prepend-self 2".
>>>>
>>>> Now, time for the questions :
>>>> - Is it openBGPd's normal behavior ?
>>>> - Is there a way to force prepending with the 2 bytes AS ? I saw
>>>> "announce as-4byte (yes|no)" in manpage, is this option designed for that ?
>>>>
>>> OpenBGPD will prepend with AS_TRANS (23456) if the system has a 4-byte AS.
>>> This comes from the fact that internally all AS_PATHes are 4-byte and we
>>> "deflate" the AS_PATH for those session that can only handle the 2-byte
>>> ones. Doing that causes all 4-byte AS nummbers to be replaced with
>>> AS_TRANS.
>>>
>>> What 2-byte AS are you using for the old connection? By default AS_TRANS
>>> would be used and then enforce neighbor-as would not trigger.
>>>
>>
>>
>> --
>> OCEANET
>> ---------------------------------------------------------------
>> [AGENCE DU MANS]
>> 7, rue des Frênes
>> ZAC de la Pointe
>> 72190 SARGE LES LE MANS
>> [t] +33 (0)2.43.50.26.50
>> [f] +33 (0)2.43.72.21.14
>>
>> [AGENCE D'ANGERS]
>> 5, rue Fleming
>> Angers Technopole
>> 49066 ANGERS
>> [t] +33 (0)2.41.19.28.65
>> [f] +33 (0)2.52.19.22.00
>>
>> http://www.oceanet.com
>> http://www.oceanet-telecom.com
>>
>
>
> --
> OCEANET
> ---------------------------------------------------------------
> [AGENCE DU MANS]
> 7, rue des Frênes
> ZAC de la Pointe
> 72190 SARGE LES LE MANS
> [t] +33 (0)2.43.50.26.50
> [f] +33 (0)2.43.72.21.14
>
> [AGENCE D'ANGERS]
> 5, rue Fleming
> Angers Technopole
> 49066 ANGERS
> [t] +33 (0)2.41.19.28.65
> [f] +33 (0)2.52.19.22.00
>
> http://www.oceanet.com
> http://www.oceanet-telecom.com
>
--
OCEANET
---------------------------------------------------------------
[AGENCE DU MANS]
7, rue des Frênes
ZAC de la Pointe
72190 SARGE LES LE MANS
[t] +33 (0)2.43.50.26.50
[f] +33 (0)2.43.72.21.14
[AGENCE D'ANGERS]
5, rue Fleming
Angers Technopole
49066 ANGERS
[t] +33 (0)2.41.19.28.65
[f] +33 (0)2.52.19.22.00
http://www.oceanet.com
http://www.oceanet-telecom.com
