UNC Path vs Physical Path and OS security layers

Question

I develop Windows application that write data to file located on filesystem.
I have 2 options to reach the filesystem:

1. Physical path: C:\Folder\Myfile.txt
2. UNC Path (Configured RWX MyShare): \MyShare\Myfile.txt

When using UNC path, we sometimes receive "unexpected network error occurred".

I am wondering if UNC and Physical path is using different drivers/kernel modules/security layers internally in the OS?

On linux when you File.Open or File.Read, it depend on the filesystem type, each filesystem will have different implementation, you will go through different security layers. Is it the same on windows?

Questions:

1. When using UNC / Physical path, do we go via different drivers / seucity layers?
2. When Using UNC, Could it be Endpoint protection/Firewall/Antivirus might add additional security layer?

Answer 1

Hello Hooked,

When working with UNC files there are 2 main things to take in consideration:

1. Explicitly opening for SMB communication
   RPC EPM TCP 135 - 139
   RPC over HTTPS TCP 593
   SMB (for named pipes) TCP 445
2. Resilience of network
   When the error happens, you may try to "clean" the network usage, in order to confirm if there is any local bottleneck of the computer: Run>
   ipconfig /flushdns
   nbtstat –RR
   netsh int ip reset
   netsh winsock reset

Hope this helps in your case,
Best regards,