[112183] in North American Network Operators' Group
Re: Lots of prepends - AS20912 case
daemon@ATHENA.MIT.EDU (Tomas Caslavsky)
Fri Feb 20 06:29:38 2009
Date: Fri, 20 Feb 2009 12:29:25 +0100
From: Tomas Caslavsky <tomas@caslavsky.cz>
To: Giuliano Peritore <g.peritore@panservice.it>
In-Reply-To: <20090220111538.8DF7C40AD0D@mars.noc.panservice.it>
Cc: nanog@nanog.org
Errors-To: nanog-bounces@nanog.org
Hi all,
I can only cofnirm that AS47868 is using also Mikrotik as their border
BGP router
Tomas
Giuliano Peritore wrote:
>
> The long (176) AS20912 prepend incident was due to a
> misconfiguration of a BGP router we were testing.
>
> The problem is that differently to Cisco the syntax of the
> prepend field on thius system is not a string (eg. "20912 20912
> 20912") but an integer, that the user interface _should_ limit to the
> interval 0-16.
>
> Unfortunately something has gone wrong with the syntax checker
> so you can enter a number (the number entered, thinking to Cisco
> syntax, was 20912) and the sotware interpreted it as the request of
> 20912 prepends... (0x51B0), dropped the highest 8 bits and processed
> it as the request of 0xB0=176 prepends.
>
> The producer has been warned about the problem, which I can't
> completely define as a "bug"... but the lack of a user configuration
> helper (syntax checker).
>
> I think that the case of AS47868 is the same, because I seed
> the modulo was involved too.
>
> Many thanks to one of our upstream providers for their support.
>
>
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