How to force the use of IPv4 on dual stack for resolving domains?

Hi everyone,

I use Checkmk, among other things, to monitor the connectivity of internet routers.
Since some internet connections use dynamic public IP addresses, a DynDNS service is set up on the routers. Some routers have dual stack with public IPv4 and IPv6 addresses, others are only reachable via IPv6 (dual stack lite/carrier-grade NAT).
In Checkmk I created a host for each router with the IP address family “IPv4 only” and the DynDNS address as IPv4 address and applied the rules “Check hosts with PING” and “Hosts with dynamic DNS lookup” to the hosts.

The network in which the Checkmk server is located does not have a native IPv6 connection, but uses a tunnel broker (6in4) for IPv6. My goal is that as little traffic as possible from the Checkmk runs through the tunnel. Therefore, I want ICMP Check to use the IPv4 address for hosts that have dual stack. Currently, Checkmk uses IPv6 whenever an IPv6 address can be resolved for the domain.

Is it possible to force the use of IPv4, e.g. via a rule or an option in the host properties? I have not found anything on this.

My system:
CMK version: Checkmk Raw Edition 2.1.0p21
OS version: Ubuntu 22.04 LTS