I have created a simple service for receiving UDP packets and am trying to deploy in Service Fabric.
When running locally, I am able to spam packets to the service (running in local SF Cluster), but when deployed to Azure the service, and even the VM, does not receive the UDP packets.
I even RDPed into the VM and installed Wireshark, my packets weren't present. I did the same with a standard Windows DC VM, and was able to see the packets arrive.
Clearly there is an issue with the firewall which is configured upon creation of a SF cluster.
PS I have followed the steps here https://learn.microsoft.com/en-us/azure/service-fabric/service-fabric-connect-and-communicate-with-services to ensure that the LB rule is set to UDP (as is not an option upon creation).
EDIT - Note I also followed the advice on this question Service Fabric Stateless Server Custom UDP Listener
So turns out that modifying an existing Load Balancer rule does not change the protocol on the firewall (speculation).
I created a NEW Load Balancer rule with the appropriate protocol/port and traffic was flowing.
Modifying an existing Load Balancer rule to change to an appropriate protocol does not work, and traffic ends at firewall.