39D The 39D Network ToolboxPublic network diagnostics and routing intelligence

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ASN to IP Prefix List

Convert an autonomous system number into a sorted IP prefix list using RIPEstat BGP announcement data, with optional safe CIDR aggregation and downloadable text output.

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ASN to IP Prefix List

Public targets only

The export is built from prefixes currently visible for the ASN in RIPEstat routing data. Aggregated mode only combines fully covered sibling CIDRs and does not add gaps.

HOW IT WORKS

About the ASN to IP Prefix List

The toolbox asks RIPEstat for the prefixes currently announced by the requested ASN. In Aggregated mode, exact sibling CIDRs are repeatedly combined into their parent only when the combined network is fully covered, so the export does not invent gaps. The resulting list is numerically sorted and can be downloaded as a plain-text file.

How to use this result

  1. Enter the ASN.Use AS followed by the number, for example AS34979.
  2. Choose IPv4, IPv6 or both.The default matches common firewall and address-list use: IPv4.
  3. Choose the export mode.Aggregated produces the shortest safe CIDR list; Announced preserves the prefixes returned by the routing-data source.
  4. Download the text file.The result preview includes a Download .txt button and the Copy button copies the complete export.

Common interpretation issues

  • The export represents BGP announcements visible to RIPE RIS, not every address block legally registered to the organisation.
  • A more-specific announcement may be intentionally separate for traffic engineering; Aggregated mode is intended for ACL, reference and address-list use.
  • Routing changes can alter the list over time, so regenerate the export when current data matters.

NEED HELP INTERPRETING THE RESULT?

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Frequently asked questions

Does the list contain every IP owned by the ASN holder?

No. It contains prefixes currently announced by that ASN in the routing data returned by RIPEstat. Registered but unannounced address space is not included.

What does Aggregated mean?

Where two exact sibling CIDR blocks completely fill their parent block, the tool combines them. It never combines ranges when doing so would include an unlisted gap.

Can I export IPv6?

Yes. Choose IPv6 or IPv4 and IPv6 before running the export.