[126509] in North American Network Operators' Group
RE: useful bgp example
daemon@ATHENA.MIT.EDU (Jeff Harper)
Wed May 19 14:37:51 2010
Date: Wed, 19 May 2010 13:37:32 -0500
In-Reply-To: <8B6E58DA-0DD3-43EC-AEDC-7DECDF2DA3FD@puck.nether.net>
From: "Jeff Harper" <jharper@first-american.net>
To: "Jared Mauch" <jared@puck.nether.net>
Cc: nanog@nanog.org
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
> -----Original Message-----
> From: Jared Mauch [mailto:jared@puck.nether.net]
> Sent: Wednesday, May 19, 2010 1:29 PM
> To: Jeff Harper
> Cc: Deric Kwok; nanog@nanog.org
> Subject: Re: useful bgp example
>=20
> Nice, but you don't show it as-path filtering your transits out. I
> frequently see people take something learned from transit A and
sending
> 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.
>=20
> - 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,
lol.
network 1.1.1.0 mask 255.255.0.0
ip prefix-list NETZ description The networks we advertise via BGP
ip prefix-list NETZ seq 10 permit 1.1.1.0/16
ip prefix-list NETZ seq 1000 deny 0.0.0.0/0 le 32
