What does the nslookup command show? Something like
Server: 127.0.0.11
Address: 127.0.0.11#53
Non-authoritative answer:
Name: mydomain.duckdns.org
Address: 11.22.33.44 #as in your current public IP?
What does the nslookup command show? Something like
Server: 127.0.0.11
Address: 127.0.0.11#53
Non-authoritative answer:
Name: mydomain.duckdns.org
Address: 11.22.33.44 #as in your current public IP?