Windows 10: Why is Windows Defender Firewall blocking an inbound port?

I have Windows 11 and am using Xfinity as my ISP. I have port forwarded Port 2346 in my router.In Defender Firewall I have set up an Inbound Rule for Port 2346 to "Allow the connection."Defender Firewall is still blocking the port. I know it is Defender Firewall because if I turn it off then the port is no longer blocked. When I turn Defender Firewall back on the port is blocked. How do I fix this so that I can keep Defender Firewall running and not block the port?

:)

 

Windows firewall: e-mail is on, yet inbound port 143 (imap) is blocked

Hi Cacadril,

We appreciate you for being a part of Windows 10.

Before proceeding, we need more information to help you better.

• 
  Are the computer connected to domain network?
  
• 
  Which are the email accounts you are working on? Is it Outlook.com/Office Outlook/other email accounts?
  

Until you get back to us with required information, I suggest you to refer to the suggestions.

Windows Firewall filters information coming into your PC from the Internet, blocking potentially harmful programs. Follow the below steps to access the interface and rules.

• 
  Open the start menu, type firewall in the search box and select
  Windows Firewall.
  
• 
  Click on Advanced settings on the left navigation pane.
  
• 
  Enter the admin credentials if any dialog box prompted.
  
• 
  In advanced settings panel, you may change the settings related to Inbound rules/Outbound rules/connection security rules/monitoring.
  

Note: If your PC is connected to network, you might not be able to change your Windows Firewall settings because of network policies. Contact your administrator for more information.

Kindly let us know the required information if you need any further assistance with the issue. We are glad to assist you.

Thank you.

 

Windows 10 Defender Firewall blocking all inbound connections - even with ports open

I've has prbolems with the Windows 10 Defender / Firewall which I've had to totally disable in order to allow inbound connections for RDP and Steam.

I've setup inbound rules on port 3389, and enabled Remote desktop assistance and with Windows Firewall running I can RDP onto the machine. If I disable Windows Defender (completely) I can access the machine through RDP.

Any ideas why this is happening? I don't really like the idea of having the FW switched off completely.

 

Inbound Firewall Rule that Blocks

Code:

Please help me understand how the 2 Inbound Rules created by MMC actually operate.

Action, Enabled, Service, Program,                     Protocol

Block,  Yes,     Any,     C:\windows\system32\mmc.exe, TCP

Block,  Yes,     Any,     C:\windows\system32\mmc.exe, UDP
If these 2 rules were Outbound Rules, I'd say that client process 'mmc.exe' is blocked.

But applying equivalent logic (that 'mmc.exe' is blocked) to Inbound Rules doesn't make sense -- why would 'mmc.exe' (which created these Rules) block itself?

What (somewhat) makes sense is that 'mmc.exe' is a requester, and that these rules block all TCP & UDP datagrams & all processes.

If so, then there's quite a difference between Outbound & Inbound Rules.

In Outbound Rules, 'Program' specifies the target (the process that's blocked), whereas in Inbound Rules, 'Program' specifies the requester (the process that provokes blocking).

This is crucial reasoning because, if correct, then, as a consequence, every process is the target of Inbound Rules that Block.

What about Inbound Rules that Allow? I've always assumed that an Inbound+Allow means the specified 'Program' installs a listener (i.e., has handler(s) for the specified socket(s)).

I think that's pretty straightforward.

I've read what Microsoft provides and it's grossly inadequate -- what a surprise, eh?

Microsoft documentation presents only trivial explanation of how to complete the fields (example: "Type the path to the program in the text box"), or the tutorial's scope is limited (example: "On the Action page, select Allow the connection, and then click
 Next" -- no mention of "Block the connection").

Other web hits are just plain wrong (examples: "Program – Block or allow a program"; "Program - creates rule that controls connections for an app or program"; "if you are downloading a file through BitTorrent, the download of that file is filtered through an
 inbound rule" -- Rules control connections, not streams) or show ridiculous cases (example: "I want to block all outgoing connections on port 80").
Does anyone know of an architectural reference or guidebook that explains how Firewall Rules are implemented in a running system?
Warm Regards -- Mark.