What happens in background when a local file is accessed over the network

Question

If I share a file which is i.e. located at C:\share\somefile.txt to the network what happens when I call it on my computer this way \\MYCOMPUTER-PC\share\somefile.txt. Does the communication flow over the network or does the OS recognize the file I want access is locally stored and goes through the file system without using the network?

In short:

There is a file: C:\share\somefile.txt shared to the network.

Does the OS make a difference between this call C:\share\somefile.txt and this \\MYCOMPUTER-PC\share\somefile.txt when it's executed on the same computer it got shared from to the network?

Answer 1

It's going through the OS network stack, but that doesn't mean it's actually going over the wire to your router and back. To check, you need to:

$ nbtstat -a MYCOMPUTER-PC

That should indicate what the IP address your computer has. Then, check the routing table with:

$ route print

To determine what interface that IP address is going over. If it's the localhost 127.0.0.1 interface, the OS will route it itself, otherwise, I believe it is going to the router and back.