Testing the Dynamic DNS client in OPNsense

[seamus]

Is there any way to test that my OPNsense DynamicDNS client is working properly? Of course it will be tested eventually when my ISP changes it, but I may not have access to my firewall when that happens (I travel a lot).

Details follow:
I use OPNsense for a number of reasons. One of the features that is particularly important to me is the VPN feature as it allows me to connect to resources on my home network while I am away on travel (which is very frequently). My sw version is: OPNsense 19.1-amd64

Following is a summary of my network configuration:
My ISP provides a "cable modem" box. To use OPNsense, I configure this modem to operate in "bridge mode". In my network, the cable modem faces the Internet, my "WAN-side" OPNsense fw/vpn adapter is connected to the "LAN side" of the modem, and then my home network is connected to the LAN-side adapter of my OPNsense fw/vpn. Everything works reasonably well until my ISP decides to change things around. One of the things that they are changing more frequently now is the routable IP address assigned to my modem. I have decided that it is time to add Dynamic DNS.

Dynamic DNS to the rescue:
To that end, I've gotten an account at "freeDNS", and a hostname to use for my OPNsense fw/VPN server. I've also set up the Dynamic DNS service in the webGUI. AFAIK, things are working as they should, but I've learned over the years that assumptions often lead to failure and disappointment. And so I want to test my Dynamic DNS configuration to make sure it works as it should. This is where I need help: I can find nothing in the docs that describes a test procedure.

How to Verify Dynamic DNS is operating correctly?:
Of course I will get a test when my ISP eventually changes the IP address of my cable modem, but I may be out of the country when that happens. I'd like some way to verify that things are working properly now - while I am still in  position to make necessary changes. Any suggestions?