nanog mailing list archives

Re: CIDR Utilization


From: inetjunkmail <inetjunkmail () gmail com>
Date: Mon, 2 Nov 2015 08:11:42 -0500

Learned that attachments do make it to the list.  Here's a link:
http://pastebin.com/tMdcfvji


On Sat, Oct 31, 2015 at 10:29 AM, inetjunkmail <inetjunkmail () gmail com>
wrote:

Attached is a perl script I wrote for a coworker that you can tweak as
you'd like.  It's designed to log into a router and dump the route table(s)
and find used/unused subnets in a given supernet.  Available routes are
green and used routes are red.  Yellow routes are routes where we have
route and a more specific route so the first route is probably an aggregate
and there _may_ be open space available.

On Fri, Oct 30, 2015 at 8:51 PM, John Steve Nash <
john.steve.nash () gmail com> wrote:

Hi,

I'm looking for any tool or a way I could specify a CIDR and the prefixes
that are being used within this CIDR and the tool show me all free
supernets.

Example:

192.168.0.0/24 - CIDR

Used subnet's:

192.168.0.1/32
192.168.0.8/27
192.168.0.64/26
192.168.0.68/32
192.168.0.96/29

Tool Result => Free Subnet's:

192.168.0.2/31
192.168.0.4/30
192.168.0.32/27
192.168.0.128/25

Regards,

John





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