MikroTik strikes again ?
a.harrowell at gmail.com
Mon May 3 05:48:42 CDT 2010
On Monday 03 May 2010 11:25:45 Bret Clark wrote:
> Uhm....okay...but why does anyone prepend their ASN that much? Are you
> saying the Mikrotik did that on purpose?
There was a well-known routing incident last year in which a difference
between the Mikrotik and Cisco CLIs caused the propagation of extremely long
AS-PATH attributes, which caused certain Cisco routers to crash.
Basically, someone remembered their Cisco IOS syntax and typed "bgp-prepend
47868" into a Mikrotik; the correct syntax would have been "bgp-prepend x
47868" where x is an integer between 0 and 16 representing the desired number
of prepends. The Mikrotik correctly tried to prepend 47868 47868 times, but
had only one byte to store this value and therefore produced 255 prepends.
Some Cisco machines, it turned out, had a bug that caused path lengths close
to 255 to crash them. Fun and games ensued.
The Renesys blog has much, much more:
The only thing worse than e-mail disclaimers...is people who send e-mail to
lists complaining about them
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