If you are planning a gradual transition from IPv4 to IPv6 in your network and want to maintain some IPv4 addresses while introducing IPv6, you can facilitate interoperability between these two protocols using several techniques on a MikroTik device.

However, you cannot directly “route” an IPv4 address to an IPv6 address natively, as they are incompatible at the protocol level. But there are strategies to allow communication between IPv4 and IPv6 devices on your network.

Strategies to Manage IPv4 and IPv6 in MikroTik

1. NAT64/DNS64
   • NAT64 is a technique that allows IPv6 devices to communicate with IPv4 servers. This technique converts IPv6 addresses to IPv4 addresses when leaving the IPv6 network and entering the IPv4, and vice versa. In MikroTik, although there is no direct support for NAT64, you can configure NAT rules to simulate this behavior in certain scenarios.
   • DNS64 is complementary to NAT64, allowing IPv6 devices to resolve domain names that only have IPv4(A) records by automatically generating AAAA records with synthetic IPv6 addresses that point to the NAT64 translation.
2. Proxy or Gateway
   • Configuring a device (such as a dedicated server or appliance) to act as a proxy or gateway between IPv4 and IPv6 can be a viable solution. This device would have interfaces on both networks and handle traffic translation or routing as needed.
3. IPv6 tunnels
   • For reverse communication (IPv4 to IPv6), you can configure tunnels that encapsulate IPv6 traffic within IPv4. This is most common for connecting IPv6 islands over an IPv4 infrastructure. MikroTik supports various types of tunnels such as IPIP, GRE, or 6to4 that can be configured for this purpose.

Considerations

• Dual Stack: The simplest and most recommended solution to manage the coexistence of IPv4 and IPv6 is to implement a dual stack configuration where devices and servers operate with both protocols simultaneously. This reduces the need for translation between protocols and simplifies network management.
• Performance and Complexity: Any form of translation or tunneling between IPv4 and IPv6 can introduce additional latency and complications in network configuration and diagnosis. It is important to evaluate the impact on performance and security before implementing these solutions.
• MikroTik Support: Make sure your version of RouterOS on MikroTik devices supports the necessary configurations for IPv6, NAT, and tunneling if you decide to use these techniques.

In summary, while MikroTik offers several tools to manage the transition and coexistence of IPv4 and IPv6, the choice of strategy depends on your specific network needs, available technical skills, and the performance and security requirements of your infrastructure.

Implementing a dual-stack configuration where possible is usually the most effective and least problematic option.