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IRR Route Filter Generator

disabled

This tool generates router prefix-list / AS-path filter configurations. It's a config-generator for network operators, not an interactive query, so it's disabled in the public version.

This tool is registered in the catalog so you can see what's planned, but the runtime is disabled in the public version.

Monitor IRR Route Filter Generator automatically

Generate router prefix-list and AS-path filters from IRR data. NetTests can run this check on a schedule, preserve historical results, compare changes over time, and alert you the moment something breaks.

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Frequently Asked Questions

What is an IRR and why does it matter?

The Internet Routing Registry (IRR) is a distributed database where network operators publish their routing policies — which IP prefixes they originate and which ASNs they transit. A filter generator queries the IRR to build prefix-lists and AS-path filters that routers use to accept only legitimate routes from peers, preventing route leaks and hijacks.

What is a BGP route leak and how do filters prevent it?

A route leak occurs when an AS re-advertises routes it shouldn't — typically a customer that re-announces its upstream's full table to another upstream, causing unexpected traffic flows. IRR-generated prefix-lists and AS-path filters on peering sessions ensure each peer only sends the routes they're authorized to originate, limiting the blast radius of misconfigurations.

How is a route filter generated from IRR data?

The generator queries IRR databases (RADB, RIPE, ARIN) for a peer's AS-SET and route objects, expands them to the full list of prefixes and origin ASNs, and writes prefix-lists and AS-path filters in the syntax of the router: Cisco, Juniper, BIRD or OpenBGPD. Regenerating the filters on a schedule keeps them in step with what each peer has registered.