Dash Network Server is a Dash App which allows you to run either a TCP/IP Server on your Controller that is capable of receiving standard TCP and/or HTTP Connections from other devices and trigger any custom macros from there.
Another way to think of the Dash Network Server is that it is essentially a tool to build your own IP Control Protocols for your Home Automation Controller. When you want to control say a Denon IP A/V Receiver, you will create an IP Driver which follows the protocol provided to you by Denon. This protocol provides a list of commands that you can send to its “Control Port” that will tell the A/V Receiver to do something. With Dash Network Server, you are providing the list of commands and the Control Port (or ports) that should be used.
Many people understand HTTP as the code and protocol used to power Internet Browsing, but it can also be used to provide a communication layer between devices. Many Control & Integration API’s have moved to HTTP for their protocols since they are understood by a wider range audience.