Configuration of shared address space RFC6598

[Netmart]

Hello,

I was wondering, if someone has experience with using and set up of IP routing with Shared Address Space, RFC 6598, 100.64.0.0/10.

Thanks,

netmart

[Francesco Molino]

Hi

Can you clarify your needs please?
I mean, do you want to interconnect your network with your provider who is using these IPs?
Or do you want to use these IPs in your network?

This is a reserved supernet for CGN. i personally use them sometimes when customer runs out of ipv4 adresses. But to specify, I don't use them for users or services, just for interconnection purposes. Which means that you can play with routing without issues. The only thing you need to make sure is to not use them to interconnect with your provider and not to advertise them to your provider.
I also use this IPs in my docker nat configuration when playing with networking stuff to make sure i won't overlap with customers subnets when distributing them.

[Netmart]

Thank you Francesco.

Basically, I want to set up a lab first, client/server scenario:

Client --Priv IP 10.1.0.0 /16--switch---FW===P2P [outside]===FW----switch- Private IP 10.2.0.0/16 ---Server.

I would like to configure the outside network by complying with RFC 6598 [Address Space, 100.64.0.0/10] .

What interfaces do get IPs from these RFC6598 assigned and what routes are required to be implemented?

[Georg Pauwen]

Hello,

on a side note, in order to use CGN NAT, your router needs to support the 'ip nat settings mode cgn' global command. I am not sure which routers and/or IOS versions do support that, it doesn't work in GNS3.

[Francesco Molino]

Setting this on your outside interface means you really want to implement gcn?
As @georg said, this is not working on all devices.

Just for my own information, what are you really trying to achieve?