[Stefan-H]

In your first scenario, any connections established through the ISP-A's IP address would be routed back through the VPN connection that they came in on. If that server were to establish it's own connections to external resources, it would feasibly be able to use the 10g connection from ISP-B. It would not be able to dictate what source address was used with connections coming from ISP-B.

[jcalvinowens]

It could work the way OP described if they routed all outbound traffic via ISP-A regardless of source address, and ISP-A allowed spoofing. I think that's what they meant.

[Habgdnv]

It is common practice for business subscribers (around UK) to get a /29 On the router we add a single /32 via the tunnel.

I think even the cheapest 100bucks business plans from many ISPs come with /28 or /29. It is a complete waste because we had like 10 offices with 3-5 persons with laptops and NO servers. The common question from the ISPs is: Do you need some IPs? When we answer no, they give us /29.