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Port 10243 · TCP

Port 10243: Windows Media Player network sharing

Media streaming from Windows Media Player's library to other devices on the network.

Protocol
TCP
On Windows
wmpnetwk.exe (Windows Media Player Network Sharing Service)
Risk if open to the internet
Medium

Seeing it on your PC

A listener on 10243 when media streaming is turned on.

Should you block it?

Local network only. If you do not stream from this PC, turn media streaming off.

Check it on your PC

Run this in PowerShell to see what is using port 10243 right now, and which program owns it:

Get-NetTCPConnection -LocalPort 10243 -ErrorAction SilentlyContinue | Select-Object LocalAddress,LocalPort,RemoteAddress,RemotePort,State,@{n='Process';e={(Get-Process -Id $_.OwningProcess -ErrorAction SilentlyContinue).ProcessName}}

No output means nothing is using the port at the moment. For every connection at once, paste netstat -ano into the netstat explainer.

Block it in Windows Firewall

In PowerShell run as administrator, this stops other computers from connecting to this port on your PC. It does not stop your own programs connecting out.

New-NetFirewallRule -DisplayName "Block inbound TCP 10243" -Direction Inbound -Protocol TCP -LocalPort 10243 -Action Block

Undo it with Remove-NetFirewallRule -DisplayName "Block inbound …", using the same name. If you depend on the service on your local network, this rule stops that too.