Im interested in thoughts for a scenario where you want to do small-scale multi-site activities, with site-to-site connectivity.

Here’s a couple of constraints:

• you’re not going to pay the money to get an assignment, you’ll just have ISP global.

• your two or more sites will have different ISPs.

• You’re doing VPN between sites instead of provider managed. The sites might be running some normal enterprise services like active directory, or other internal corporate norms.

• you might have the need for a backup Internet connection. Load balancing would not be required.

With the fact that the globals could change at a site, would you consider using ULA? Or just stick with global and update DNS in the event of change. I know there’s a preference problem with ipv4 being chosen over ULA, so the ULA thing wouldn’t be very easy unless you went straight v6.

If ULA, would you pattern/convention match the global in each site or create one organization wide ULA and assign it something like /48 per site?

What precautions do you take on gateways to ensure globals aren’t used outside of the tunnel? ULA prevents this, but so does proper configuration I assume.

How would you do this?

I keep asking about ULA because I heard/read enough articles where the author says don’t do it, but they seem to be geared at large enterprise or hosting where they would definitely get dedicated blocks, peering, etc. I’m interested in the little guy.