SMB - File and printer sharing ports should be open (2024)

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Applies To: Windows Server 2022, Windows Server 2019, Windows Server 2016, Windows Server 2012 R2, Windows Server 2012, Windows Server 2008 R2

When a Best Practices Analyzer scan for Server Message Block (SMB)-based network services identifies that firewall ports for file and printer sharing aren't open, follow the steps in this article to resolve the issue.

Operating systemProduct/FeatureSeverityCategory
Windows ServerFile ServicesErrorConfiguration

Note

This article addresses a specific issue identified by a Best Practices Analyzer scan. Apply the information in this article only to computers that have a File Services Best Practices Analyzer scan that reports the specific port issue. For more information about best practices and scans, see Best Practices Analyzer.

Identify the issue

A File Services Best Practices Analyzer scan reports that firewall ports necessary for file and printer sharing aren't open (ports 445 and 139).

The issue prevents computer access to shared folders and other SMB-based network services on the server.

Resolve the issue

To resolve the issue, enable file and printer sharing to communicate through the computer's firewall. To complete the procedure, you must be a member of the Administrators group (or equivalent), at a minimum.

To open the firewall ports and enable file and printer sharing, complete the following steps:

  1. Open Control Panel, select System and Security, and then select Windows Defender Firewall.

  2. On the left, select Advanced settings. The Windows Defender Firewall console opens and shows the advanced settings.

  3. In the Windows Defender Firewall console on the left, select Inbound Rules.

  4. Under Inbound Rules, locate the following two rules:

    • File and Printer Sharing (NB-Session-In)

    • File and Printer Sharing (SMB-In)

  5. For each rule, select and hold (or right-click) the rule, and then select Enable Rule.

SMB - File and printer sharing ports should be open (2024)

FAQs

What ports are SMB file and printer sharing? ›

SMB has always been a network file sharing protocol. As such, SMB requires network ports on a computer or server to enable communication to other systems. SMB uses either IP port 139 or 445.

How do I enable file and printer sharing SMB? ›

Open the Control Panel and click on Network and Sharing Center. Click on Change advanced sharing settings on the left. Expand Private, Guest or Public, or All Networks for the one you want. Click on Turn on file and printer sharing or Turn off file and printer sharing.

What ports need to be open for SMB? ›

SMB is a network file sharing protocol that requires an open port on a computer or server to communicate with other systems. SMB ports are generally port numbers 139 and 445. Port 139 is used by SMB dialects that communicate over NetBIOS.

What ports should I open for my printer? ›

The destination port for the printer hardware is always reflected in the Port number (PORT) parameter in the printer device description, so that can be a good place to look. The most common destination ports are 2501, 5001, 9100, 9101, 9102, and 9600; however, some printers could use other ports.

How do I know if my SMB is open? ›

Check SMB status: Check the status of the SMB service by running the command "Get-Service -Name "LanmanServer"" in PowerShell. This command will display the status of the LanmanServer service, which is responsible for the SMB protocol.

What is the best port for SMB? ›

The shift from port 139 to 445 marks a significant evolution in SMB communication, primarily driven by the need for more secure and efficient networking solutions. Port 445 allows SMB to operate directly over TCP/IP, bypassing the older NetBIOS layer, which is less secure and more complex.

Should I turn off file and printer sharing? ›

Turning off file sharing will prevent wireless access to files on your computer over the network you're connected to, thus making your computer more secure. Faculty and staff: Make sure you do not need these services before disabling them.

How do I find the SMB of my printer? ›

SMB-connected print server
  1. Click Start, point to Settings, and then click Printers.
  2. Double-click Add Printer, and then click Next.
  3. Click Local Printer, and then click Next.
  4. Click Create a new port.
  5. In the Type box, click Local Port, and then click Next.
  6. Type the SMB share name.

What does SMB printer mean? ›

Overview. The SMB printing function is a function used to print data by directly specifying this machine on the computer. This machine is shared using the SMB (Server Message Block) protocol. If the WINS server is installed to resolve the name, register it.

How to connect to SMB port? ›

How to access SMB share from windows over the internet with specific port number
  1. go to My computer.
  2. Click add network location.
  3. Enter x.x.x.x as ip (ofcourse I enter a real public IP)
  4. Then try to connect.
Dec 23, 2020

What does SMB port stand for? ›

The Server Message Block protocol (SMB protocol) is a client-server communication protocol used for sharing access to files, printers, serial ports and other resources on a network. It can also carry transaction protocols for interprocess communication.

What does SMB stand for? ›

SMB stands for Small and Midsize Business, which refers to companies or organizations with fewer employees, less revenue, and assets compared to larger enterprises. Also known as small and medium-sized enterprises, SMEs are smaller than large enterprises.

What ports are used for SMB printer sharing? ›

Ports Used for Printer Sharing
(Destination) Port(s)TCP/UDPDescription
137 (WINS)UDPWindows Internet Naming Service (name lookup for SMB printing).
139 (SMB)TCPWindows SMB printing.
445 (SMBDS)TCPWindows SMB Domain Server (authenticated SMB printing).

How do I know which port my printer should be connected to? ›

Checking the Print Port (for Windows Only)
  1. Click start, and then select Devices and Printers.
  2. Right-click the printer icon, and then click Printer Properties.
  3. Select the Ports tab to check which print port is selected. Print ports selected in the port column are available. You can check the port type from Description.

Which port is best for printer? ›

USB 3.0 printer ports are great for sole traders and home use, offering lightning-fast transfer speeds of up to 5Gbps. You can also have up to 127 different devices attached to a single USB port. Network ports – Most modern printers offer wireless printing, and this uses what are known as network ports or TCP/IP ports.

What is the SMB protocol for printers? ›

The SMB protocol is an application-level network protocol that is primarily used for sharing printers, access to files, serial ports, and miscellaneous communications between nodes on the network. Mainly used by Windows systems, SMB is an authenticated inter-process communication mechanism.

What are ports 135, 139, and 445 used for? ›

Port 135 is used for RPC client-server communication, and ports 139 and 445 are used for authentication and file sharing. UDP ports 137 and 138 are used for local NetBIOS browser, naming, and lookup functions.

What port does file and print server use? ›

In modern and supported versions of Windows, File and Printer Sharing services use TCP port 445.

What are SMB settings on a printer? ›

The SMB printing function is a function used to print data by directly specifying this machine on the computer. This machine is shared using the SMB (Server Message Block) protocol. If the WINS server is installed to resolve the name, register it.

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