Re: BGP Debug question (How to know what AS, neighbor is using

Yes, you are right on this.

The remote peer will get a similar BGP notification like

Jul 11 00:18:42.815: %BGP-3-NOTIFICATION: sent to neighbor 100.100.24.4 2/2 (peer in wrong AS) 2 bytes 0004

Bu without the rest of the hex

A.

MDevarajan_at_inautix.co.in wrote:
> There is a way to find out the correct AS..
>
> Copy the bytes value (0004) and put in calc in binary and click decimal ..
> the the value comes is the correct AS...
>
>
>
>
> Jul 11 00:18:42.815: %BGP-3-NOTIFICATION: sent to neighbor 100.100.24.4
> 2/2
>
>> (peer in wrong AS) 2 bytes 0004 FFFF FFFF FFFF FFFF FFFF FFFF FFFF FFFF
>>
> 002D
>
>> 0104 0004 00B4 6464 1804 1002 0601 0400 0100 0102 0280 0002 0202 00
>>
>>
>
> Please correct me if I am wrong.
>
> Thanks in advance,
> Mohan
>
>
>
>
>
>
> Marko Milivojevic <markom_at_markom.info>
> Sent by: nobody_at_groupstudy.com
> 08/10/2009 05:52 AM
> Please respond to
> Marko Milivojevic <markom_at_markom.info>
>
>
> To
> Joe Astorino <jastorino_at_ipexpert.com>
> cc
> Pradeep Malik <pradeepmlk_at_gmail.com>, Cisco certification
> <ccielab_at_groupstudy.com>
> Subject
> Re: BGP Debug question (How to know what AS, neighbor is using to peer
> with my IP ???????)
>
>
>
>
>
>
> Sometime ago I wrote a troubleshooting article on this subject that
> you may find useful. Get it here:
>
> http://cisco.markom.info/2008/10/peering-with-unknown-autonomous-system.html
>
>
> --
> Marko
> CCIE #18427 (SP)
> My network blog: http://cisco.markom.info/
>
> On Mon, Aug 10, 2009 at 07:31, Joe Astorino<jastorino_at_ipexpert.com> wrote:
>
>> I wanted to follow up on this with the group. B I think I misunderstood
>>
> the
>
>> original question. So I think you are asking is there a way to know what
>>
> the
>
>> incorrectly configured AS number is? B There is no way I know of.
>>
>> R2(config-router)#do sh run | s bgp
>> router bgp 2
>> B no synchronization
>> B bgp log-neighbor-changes
>> B neighbor 100.100.24.4 remote-as 99
>> B no auto-summary
>>
>> router bgp 4
>> B no synchronization
>> B bgp log-neighbor-changes
>> B neighbor 100.100.24.2 remote-as 2
>> B no auto-summary
>>
>> R2(config-router)#
>> *Jul 11 00:18:42.815: %BGP-3-NOTIFICATION: sent to neighbor 100.100.24.4
>>
> 2/2
>
>> (peer in wrong AS) 2 bytes 0004 FFFF FFFF FFFF FFFF FFFF FFFF FFFF FFFF
>>
> 002D
>
>> 0104 0004 00B4 6464 1804 1002 0601 0400 0100 0102 0280 0002 0202 00
>>
>> R4(config-router)#
>> *Aug 10 09:31:46.319: %BGP-3-NOTIFICATION: received from neighbor
>> 100.100.24.2 2/2 (peer in wrong AS) 2 bytes 0004
>>
>> On Mon, Aug 10, 2009 at 2:57 AM, Joe Astorino
>>
> <jastorino_at_ipexpert.com>wrote:
>
>>> It actually tells you exactly what you need there. B 0x0021 is the AS
>>> number. B Convert that to decimal and you are all set. So in this case,
>>> 0x0021 = AS 33
>>>
>>>
>>>
>>> On Mon, Aug 10, 2009 at 2:16 AM, Pradeep Malik
>>>
> <pradeepmlk_at_gmail.com>wrote:
>
>>>> Hi All,
>>>>
>>>> My question is; what debug cmds could we use to find out AS that
>>>>
> neighbor
>
>>>> has configured for my peering B i.e B If I am X.X.X.X and this
>>>>
> statement is
>
>>>> at B neighbor B " B bgp X.X.X.X remote-as Y" B B How to know AS Y ? B
>>>>
> If I
>
>>>> troubleshoot on my router, it only gives below notification and it
>>>>
> shows
>
>>>> hexa decimal value of AS configred at my side but not on neighbor
>>>>
> side..
>
>>>> *Dec B 9 14:25:00.010: %BGP-3-NOTIFICATION: received from neighbor
>>>> 150.2.3.254 2/2 (peer in wrong AS) 2 bytes 0021
>>>>
>>>> any suggestions ???
>>>>
>>>> Cheerz,
>>>> PM
>>>>
>>>>
>>>> Blogs and organic groups at http://www.ccie.net
>>>>
>>>>
>>>>
> _______________________________________________________________________
>
>>>> Subscription information may be found at:
>>>> http://www.groupstudy.com/list/CCIELab.html
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>> --
>>> Regards,
>>>
>>> Joe Astorino - CCIE #24347 R&S
>>> Technical Instructor - IPexpert, Inc.
>>> Cell: +1.586.212.6107
>>> Fax: +1.810.454.0130
>>> Mailto: B jastorino_at_ipexpert.com
>>>
>>>
>>
>> --
>> Regards,
>>
>> Joe Astorino - CCIE #24347 R&S
>> Technical Instructor - IPexpert, Inc.
>> Cell: +1.586.212.6107
>> Fax: +1.810.454.0130
>> Mailto: B jastorino_at_ipexpert.com
>>
>>
>> Blogs and organic groups at http://www.ccie.net
>>
>> _______________________________________________________________________
>> Subscription information may be found at:
>> http://www.groupstudy.com/list/CCIELab.html
>>
>
>
> Blogs and organic groups at http://www.ccie.net
>
> _______________________________________________________________________
> Subscription information may be found at:
> http://www.groupstudy.com/list/CCIELab.html
>
>
> Blogs and organic groups at http://www.ccie.net
>
> _______________________________________________________________________
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Received on Fri Aug 14 2009 - 21:10:48 ART