I came across this problem.
There is a host with proxmox 8 installed. I created a virtual machine with the DNS role. If I try to connect to this machine via port 53 from a physical machine on this network, I get a connection error. If I connect to this machine from another virtual machine (on this host) or from the proxmox host on port 53, then the connection goes through. Please tell me in what area to look for the problem? It is worth noting that there are no such problems with other ports; I installed Nginx and was able to connect to it from anywhere.

The firewall rules on the host are standard and have not changed. The firewall rules on the virtual machine are also standard and have not changed. Port 53 on the virtual machine is open. I tried different systems, I tried Windows Server and Debian, the result was the same. I found out through experience that the problem with the connection only applies to physical machines on the same network; if I connect from another virtual machine or from a host, the connection is established.