nanog mailing list archives
Re: BGP prefix filter list
From: "Jörg Kost" <jk () ip-clear de>
Date: Fri, 17 May 2019 11:17:30 +0200
Hi,I did this tool a few years ago to download and built ASN filter lists by region automatically:
https://github.com/ipcjk/asnbuilder/releasesThe tricky part was to build regular expressions for devices, that don't understand number ranges.
For some of our routers we (un)select ASNs manually by reading and comparing CIDR-reports to current Sflow traffic:
E.g. https://github.com/ipcjk/asnbuilder/blob/master/customASN.txt will become https://github.com/ipcjk/asnbuilder/blob/master/saveTheFIB.txt Jörg On 17 May 2019, at 10:59, Jared Brown wrote:
There are a few approaches to culling the routing table. You can do it either statically or dynamically, according to your needs.1. Filtering based on upstream communities Slimming down the Internet routing table https://www.redpill-linpro.com/sysadvent/2016/12/09/slimming-routing-table.html 2. Filtering based on region BGP filter for North American routes http://gregsowell.com/?p=5505Substitute prefixes for applicable region(s). Each region is about 200k prefixes. For more granularity use a geolocation service to select prefixes and/or ASNs.3. Using flow information to install only top routes SDN Internet Router – Part 2 https://labs.spotify.com/2016/01/27/sdn-internet-router-part-2/ https://blog.ipspace.net/2015/01/sdn-router-spotify-on-software-gone-wild.html 4. Aggregate the routing tableAccording to the weekly routing table report you can aggregate announcements to about half the number of prefixes. You need to roll your own software to preprocess the BGP feed. There are some tools out there, but I couldn't find a blog post about it with a quick search. If you have one, please share!Jared
Current thread:
- Re: BGP prefix filter list, (continued)
- Re: BGP prefix filter list Karsten Elfenbein (May 15)
- Re: BGP prefix filter list Radu-Adrian Feurdean (May 15)
- Re: BGP prefix filter list Tom Beecher (May 15)
- Re: BGP prefix filter list Alejandro Acosta (May 18)
- Re: BGP prefix filter list Amir Herzberg (May 18)
- Re: BGP prefix filter list Alejandro Acosta (May 18)
- Re: BGP prefix filter list Blake Hudson (May 20)
- RE: BGP prefix filter list adamv0025 (May 22)
- Re: BGP prefix filter list Blake Hudson (May 22)
- Re: BGP prefix filter list Amir Herzberg (May 18)
- Re: BGP prefix filter list Jared Brown (May 17)
- Re: BGP prefix filter list Jörg Kost (May 17)
- Re: BGP prefix filter list Scott Weeks (May 30)
- Re: BGP prefix filter list Valdis Klētnieks (May 30)
- Re: BGP prefix filter list Scott Weeks (May 30)