useful bgp example

Jeff Harper jharper at
Wed May 19 18:37:32 UTC 2010

> -----Original Message-----
> From: Jared Mauch [mailto:jared at]
> Sent: Wednesday, May 19, 2010 1:29 PM
> To: Jeff Harper
> Cc: Deric Kwok; nanog at
> Subject: Re: useful bgp example
> Nice, but you don't show it as-path filtering your transits out.  I
> frequently see people take something learned from transit A and
> it to transit B, and if it happens to be the backup path in-use for
> your customer, your transits will accept it and likely pick you as
> best-path and hairpin through your network.
> - Jared

Yeah, I left out the actual prefix-list contents, in hindsight I should
have added it, so here it is. Also, a typo in the network statement,

network mask

ip prefix-list NETZ description The networks we advertise via BGP
ip prefix-list NETZ seq 10 permit
ip prefix-list NETZ seq 1000 deny le 32

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