Why is udp port 137 being used during a remote desktop session?

I'm currently seeing a lot of messages on my firewall stating that udp port 137 is being blocked.  I suspect that when I use remote desktop to a remote system, that remote systems attempts to connect back to me via udp port 137.  If this is true, why?  Is this required or can I change this behavior?


UDP 137 is used by NetBIOS File sharing in Windows 7.

Depending on what you do while you are using Remote Desktop on your network, it might invoke the UDP137.

If it does not impede anything functional that you need to do, leave it alone. The firewall Job is to block aspects of Network traffic. You do not have to feel "sorry" for it doing its Job.


Jack-MVP Windows Networking. WWW.EZLAN.NET
Jack MVP, Microsoft Windows Desktop Experience-Networking.


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Question Info

Last updated April 20, 2020 Views 13,981 Applies to: