Can not Access Windows Network Folder Share With Netbios. With IP you can access the shares

I had a strange case on windows server allowing access to the shared folder on the server with IP only, when trying to access with netbios name or FQDN of the server. no response pop, no credential pop-up. some times I got “you do not have permission to access the folder …” .

Eventual it came down to the Windows Firewall settings, here is what needed :

Windows Firewall doesn’t directly control name resolution (such as NetBIOS or DNS translation), but it does include rules that are critical for enabling protocols used in name resolution and file sharing. If name resolution fails, it might be due to one of these rules being disabled or blocked.

Here’s an overview of relevant rules:

1. Rules Related to Name Resolution

NetBIOS Name Resolution

NetBIOS over TCP/IP is used for resolving NetBIOS names to IP addresses. The relevant rules are:

• File and Printer Sharing (NB-Name-In): UDP 137 (NetBIOS Name Service).
• File and Printer Sharing (NB-Datagram-In): UDP 138 (NetBIOS Datagram Service).
• File and Printer Sharing (NB-Session-In): TCP 139 (NetBIOS Session Service).

These are crucial if you’re relying on NetBIOS name resolution.

DNS Name Resolution

If you’re using DNS, ensure the following rules are enabled:

• DNS Client: Allows outbound DNS requests (UDP 53).

2. Rules Related to SMB File Sharing

Even if name resolution works, SMB file sharing requires additional rules:

• File and Printer Sharing (SMB-In): TCP 445 (SMB protocol for file sharing).

3. Verifying and Enabling Rules

1. Open Windows Defender Firewall with Advanced Security:
   • Press Win + R, type wf.msc, and press Enter.
2. In the left pane, click Inbound Rules.
3. Look for the following rules:
   • File and Printer Sharing (NB-Name-In) → UDP 137.
   • File and Printer Sharing (NB-Datagram-In) → UDP 138.
   • File and Printer Sharing (NB-Session-In) → TCP 139.
   • File and Printer Sharing (SMB-In) → TCP 445.
4. Ensure these rules are Enabled (green checkmark).

4. Testing Name Resolution

After verifying these rules:

1. Flush the DNS and NetBIOS cache on the client:

ipconfig /flushdns
nbtstat -R

2. Test name resolution using:

ping ServerName

If it resolves correctly, proceed to test access to the share:

net use \\ServerName

If you still have problem, You need to make sure that the ruled should be enabled on all profiles :

Private , Public, Domain