With the rise of IPv4 costs, IPv6-only servers are becoming more popular in low end hosting world. In one occasion, I acquired an IPv6-only server, but wanted to have IPv4 on it. Somewhere else, I have a dual-stack IPv4+IPv6 server, idling away. Can I "borrow" the IPv4 of that dual-stack server, to use on the IPv6-only server? I tried several methods, and found a way to make this work.
Situation / Assumption / Requirement
In this case, both servers have KVM virtualization and are running Debian 12 operating system.
Server A is a dual-stack server, with IPv4 address
192.0.2.158 and IPv6 address
Server B is an IPv6-only server, with IPv6 address
At server A, both IPv4 and IPv6 service are delivered on the same network interface.
My goal is to somehow "move" the IPv4 address from server A to server B.
In particular, I want all IPv4 traffic to the
192.0.2.158 destination address to reach server B, and allow server B to send any IPv4 traffic with
192.0.2.158 source address.
This shall include all TCP and UDP ports, as well as other IPv4 traffic such as ICMP ping.
A "port forwarding" solution would be insufficient, as it cannot deliver non-TCP/UDP traffic.