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Auto pull subnets from route table

Auto pull subnets from route table

In a large environment like mine, we add subnets, or break up subnets on a daily basis.  I would like to see IPAM read the route table from a list of routers and pull the smallest subnets and auto populate them into IPAM.  Due to summarization, it will need to pull from a list of routers, maybe every night, and populate the DB with the highest bits  (24bit, etc.)

This is the number one complaint I hear from my design team.  They have to manually type all this in.

Another way to do this may be pulling the interface IP's or subnets.  Then you can also pull the description off the vlan/interface.  That would be real nice...

Level 16

Make it virtual-instance aware. Here the layer-3 is virtualized where we have separate ruoting tables in routers for the virtual networks that overlay the physical infrastructure. this means that the Routing Tables and ARP tables only contain information for the routing instance you're in

Level 8

The interface information can be (or is if you perform inventory) pulled by NCM.  If the NCM and NPM databases were combined all that information would be in one spot and each module could leverage information without performing the same task twice.

I'm quite sure others know this detail above but I thought it should at least make it to the comments.



Level 13


THe ability manually and auto pull in rtr tables s needed

AS ver usage is growing, the ability topull in from multiplegrater tables

WE need Cisco,hp,juniper rtr and switch support

l2andL3 support also

Level 16

Since NPM is pulling routing tables now, couldn't that data be used for IPAM?  Maybe like an import option based on all the routing tables?

My workaround:

From a core router, with a full table view of ALL routes (we don't summarize customer routes in our core):

show ip route <supernet> <netmask> longer-prefixes | redirect tftp://linux-tftp-server/<supernet>.routes

On linux-tftp-server:

cat supernet.routes | grep -v subnetted | grep -E -o "[0-9]+\.[0-9]+\.[0-9]+\.[0-9]+/[0-9]+" | sed -e "s/\// \//" | sort -t. -k 3,3n -k 4,3n | sed -e "s/ \//\//" > supernet.sorted

Edit the sorted supernet list and remove the supernets (if existing) so all you have is the subnets.

Then just copy/paste supernet.sorted into bulk subnet import, under your supernet.

This is an easy way to start using IPAM to find free allocations, even if you don't have all customer data associated with the subnets initially, you can always massage the data later.

available in beta as functional preview of this feature, get it here: Forget the spreadhseets. IPAM has automatic subnet discovery - beta 2  and please, share your feedback if it worked or not or what you want to add. thanks a lot

implemented in 4.2

Level 7

Where is this implemented?

I am trying to add subnets from my router's routes but I fail to find how to proceed in IPAM.

I looked for some documentation on the matter and I can't find any.

Could you please tell me how/where to go on IPAM to achieve this?