BGP prefix filter list
jk at ip-clear.de
Fri May 17 09:17:30 UTC 2019
I did this tool a few years ago to download and built ASN filter lists
by region automatically:
The 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:
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
> 2. Filtering based on region
> BGP filter for North American routes
> Substitute 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
> 4. Aggregate the routing table
> According 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!
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