Mirth channel Source TCP Listener setting

I'm running mirth on Azure VM (Windows Server 2016) and trying to get HL7 messages from Meditech. Not really familiar with tcp/ip concept so help is appreciated here. When Meditech sends HL7 messages to my server (VM), how should I configure the setting in mirth's channel?

For example, in Listener Settings panel,

1.Select Specific interface and put my VM's public ip address.

2.Put port number I set in inbound rule in Local Port

or do I put Meditech's ip address and port number in Listener Settings?

TCP/IP is pretty simple. From the sending system, you specify the destination IP address and port # that you want to send to. From the destination system, you set up your listener to run on a specific port #. In Mirth you can choose to accept messages from any IP (All interfaces) or a specific IP address (specific interface) in the TCP Listener Settings:

So to address your specific example, it sounds like you want a message to go outbound from Meditech to your Mirth instance on an Azure VM. In Meditech, you would enter the Azure server's IP address and port # that you specified in Mirth. In Mirth, you can leave it open to the world and select "All interfaces," or specify your Meditech interface engine's IP address in "Specific interface."

One final thought.. I have never played around with Azure, but I'm sure there are some security settings. (hopefully it is behind a firewall of some sort) You may need to explicitly allow traffic from your Meditech interface engine's IP. If you need further help with that, I would post a new question and tag it under Azure.