YES - I have the firewall completely turned off.
This is within my private lab, I setup a new Win2016 server to play with Windows Containers. The machine has 3 network ports, and I put all 3 as exposing Hyper-V, so now I have 3 virtual switches and the network adapters are slaved to them.
There are 3 networks, lan1, lan2, lan3, and all have their own isolated access to an internet facing gateway.
Firewall is switched off, advanced firewall is switched off. The machine is not on a domain.
The install of Windows 2016 on this machine replaced a Linux Proxmox install on the same machine, with the same 3 IP's, with the same network hardware in place. So this should prove that the network is OK with addressing these IP's and should limit the problem-solving to just the configuration of the Windows Server and it's networking.
I have been installing windows Networking in some form or another since Windows'98, so am a littler perplexed.
The problem -
I can ping my firewall and other machines on the network, but no-one can ping the new machine. I turned off the firewall in an attempt to get this working.
I can remote desktop into the machine, from the machine. But I cannot reach it from any other machine on my network. I get no response from the new server.
Thinking that we may have a multi-path issue, I disabled and unplugged 2 of the 3 network adapters. The sole gigabit card pings everyone, but responds to no pings, and can remote desktop into everyone but offers no response to all remote desktops.
Other Information -
All the networks are setup as private networks.
I have another Win2016 machine running on the same configuration, 3 networks, and it all works fine. The only difference is that this other machine does not have hyper-v installed, and so does not have the virtual switches (it runs WMware Workstation for high-functioning VM's with sound and graphics etc).
What to do?