ASN to IP Mapping

Rubens Kuhl rubensk at
Sat Mar 7 21:12:50 UTC 2015

On Sat, Mar 7, 2015 at 12:37 PM, Andrew Iwamoto <
aiwamoto at> wrote:

> Is there a tool or method to determine IP blocks assigned to an
> organization by ASN?  I.e. if I have an organization's ASN number I want to
> know all blocks assigned to that ASN.

That's RIR/NIR-dependent, so you probably have to go thru all of them to
map all possible IP blocks. Other references suggested that will
only list advertised networks, and IRRs will only have IRR-listed networks.

For instance, on ARIN for AS 15141:

Find the organization name; click on the link

Find the networks link:

Network ResourcesBAUSCH-LOMB (NET-161-242-0-0-1
<>) -

Look for the other RIRs; rinse and repeat.


More information about the NANOG mailing list