Smb ports.
Apr 20, 2022 · The SMB port number is TCP 445.
Smb ports In this article, we will explore what is SMB port and the different SMB port numbers it relies on for efficient resource sharing over networks. In this article, you can find the network ports and protocols required by DSM services for operations. In modern Windows environments, port 445 is generally the primary port used for SMB traffic. Additionally, the Windows SMB client requires Ping (ICMP Echo) to be open. Windows 8 introduced several new features, so Microsoft has decided to bump the revision number up to SMB v3. Oct 7, 2020 · SMB port numbers play a vital role in network communication, serving as gateways for file sharing, printer access, and more. Ports and DPI information on the Windows SMB v2/v3 protocol. Oct 3, 2023 · SMB (Server Message Block) protocol is used for file sharing among different computers. 3-encrypted security tunnel like a VPN for the SMB traffic. This uses UDP port 443 by default and provides a TLS 1. Dec 13, 2024 · Windows 11 24H2 and Server 2025 improve the SMB protocol with a strong focus on security. However, port 139 might still be used for compatibility with older systems or applications that rely on NetBIOS Port 445 Port 445 is used by newer implementations of SMB that can operate directly over TCP/IP, without the need for NetBIOS. The introduction of alternative ports for SMB is a crucial step in Microsoft’s Secure Future Initiative, offering administrators more control over network security and access management. SMB stands for "server message block. It permits the common use of files, printing, and other network utilities. 2, requires TCP/IP over port 445. Port 139 is used by older SMB dialects that rely on NetBIOS for communication and establish network connections for shared resources like printers and serial ports, particularly in Windows operating systems. Sep 27, 2023 · The SMB protocol allows users to access files and connect resources remotely. However, they also pose security risks if not properly managed. 0 and older CIFS traffic supported the NetBIOS over TCP (NBT) protocol supported the UDP transport, but starting in Windows Vista and Windows Server 2008 with SMB 2. SMB2 Server Message Block version 2 and 3 SMB2 is a new version of the old Windows filesharing protocol SMB and is used for filesharing on modern and future Windows hosts. Mar 26, 2021 · Discover the basics around SMB protocol, port 445 and 139 and differences. It can also carry transaction protocols for inter-process communication that is authenticated. You can also configure your deployment to block configuring alternative ports or specify that ports can only connect to certain servers. Can you provide me a list of ports along with sample iptables rules? You can get list of ports from file called /etc/services. This includes copying files, directory listings and printer related operations. Port 139: SMB originally ran on top of TCP port 139 is associated with NetBIOS over TCP/IP, which is an older protocol that was commonly used for Windows file sharing before the widespread adoption of SMB over TCP/IP on port 445. You should also allow only SMB 3. In Windows Server, it's possible to host an SMB over QUIC connection on a Nov 8, 2023 · SMB server in Windows has required inbound connections using the IANA-registered port TCP/445 for decades, and the SMB TCP client has only supported connecting outbound to that TCP port. SMB continues to be the de facto standard network file sharing protocol in use today. This name appears in the output of netstat. Oct 20, 2023 · What is Port 445? by Colin Cohen | Published on October 20, 2023 Port 445 is dedicated to the Server Message Block (SMB) protocol, which allows you to share resources such as files and printers within a network using TCP. One key feature is the ability to change ports to TCP 445, which offer Jan 16, 2023 · Port 139 is used by SMB dialects that communicate over NetBIOS. Jul 31, 2025 · What Are SMB Ports? A server message block (SMB) port is a network port that allows devices on the same network to share files and resources. However, you can only connect to alternative ports if the SMB server is configured to support listening on that port. Why so many ports? Let's go into a bit of detail. Learn what implications it has on the security of the network. SMB relies on the TCP and IP protocols for transport. Interestingly Feb 4, 2025 · Learn how to change the SMB port in Windows Server 2025 and Windows 11 for better security and network control with this step-by-step guide. Dec 8, 2021 · The SMB (Server Message Block) protocol provides for “client-server communication,” allowing programs and services on networked computers to communicate. In a nutshell, the SMB protocol allows computers to communicate with one another. -p|--port<port number (s)> port number (s) is a space or comma-separated list of TCP ports smbd should listen on. Is Samba a TCP or UDP? Samba TCP Ports Most SMB/CIFS network traffic by volume occurs over TCP. Jan 15, 2025 · SMB 1. 100\share_name opposed to \\my_file_server\share_name So port 445 is sufficient if you can work with IP addresses only. Knowledge of these ports is important for a good understanding of network Apr 19, 2022 · The SMB protocol is a client–server communication protocol that has been used by Windows since the beginning for sharing files, printers, named pipes, and other network resources. This has been allocated the network service name netbios-ssn by the Internet Assigned Numbers Authority (IANA). SMB handles file sharing and printer access between machines. The protocol has since spawned multiple variants, also known as dialects, to meet evolving Sep 25, 2025 · The operations of DSM services require specific ports to be opened to ensure normal functionality. Understanding the differences between SMB versions is crucial for securing your network. The most important working part of the SMB protocol is the ports through which operates, these include ports 445 and 139. Note, however, that many residential ISPs globally block WAN connections from/to these ports, due to the large amount of worms attacking unpatched SMB servers. Aug 4, 2016 · SMB uses ports 445/tcp and/or 139/tcp (usually just one is enough, but sometimes it's better to forward both). Also note that the Windows SMB client always uses Nov 1, 2024 · You can use the SMB client to connect to alternative TCP, QUIC, and RDMA ports. Commonly included as a basic system service on Unix-based operating systems. Unfortunately the consumer electronics Router I work with blocks port 445 and 139 for security considerations (netbios attacks), without any option to disable the blocking. With Windows 11 and Windows Server 2022 Datacenter: Azure Edition, you can use SMB over QUIC to connect to file servers in Azure. x traffic and require SMB AES-128 encryption. It can be a very 139,445 - Pentesting SMB Tip Learn & practice AWS Hacking: HackTricks Training AWS Red Team Expert (ARTE) Learn & practice GCP Hacking: HackTricks Training GCP Red Team Expert (GRTE) Learn & practice Az Hacking: HackTricks Training Azure Red Team Expert (AzRTE) Port 139 The Network Basic Input Output System ** (NetBIOS)** is a software protocol designed to enable applications, PCs, and What is Microsoft Server Message Block (SMB) Protocol, How to determine, Enable and Disable of SMBv1, SMBv2, and SMBv3 in Windows server 2016 to 2008 and Win10? Apr 11, 2025 · SMB (Server Message Block) is widely used for network file sharing on Linux, Windows, and macOS environments. SMB serves as the basis for Microsoft's Distributed File System implementation. If you have old clients in your network, the earlier version of SMB (SMB 1. Example \\192. It can also carry transaction protocols for interprocess communication. Mar 27, 2024 · What are Ports 139 and 445? SMB requires specific ports to facilitate communication between computers and servers: ports 139 and 445. Read about whether SMB is secure and how to protect against dangerous attacks. Sep 14, 2023 · An SMB port is a network port commonly used for file sharing. 1 Windows SMB Ports and Protocols # Originally, in Windows NT, SMB Jul 10, 2025 · The Server Message Block (SMB) Protocol is a network file sharing protocol, and as implemented in Microsoft Windows is known as Microsoft SMB Protocol. cmd == 0x11. This comprehensive article will explore what an SMB port is, and detail the functions of Port 445 and Port 139, revealing their crucial roles in file Sep 18, 2015 · The SMB protocol that I configured uses Port 445 at some Point. Let’s understand the SMB ports 445, 139, 138, and 137 in detail. Those ports are 137, 138 and 139. This article is all about SMB, how it works and what ports it uses. For Windows NT4 and below, all this traffic occured over TCP port 139. Samba TCP Ports Most SMB/CIFS network traffic by volume occurs over TCP. One of the most important protocols that utilizes ports is SMB (Server Message Block), which is widely used for file and printer sharing among Windows devices. Mar 22, 2023 · Learn how to keep file and printer sharing ports open for Server Message Block (SMB)-based network services and resolve the Best Practices Analyzer scan issue. Mar 4, 2025 · Explore SMB Port: secure remote access alternatives and best practices. The name Samba comes from SMB (Server Message Block), the name of the standard protocol used by the Microsoft Windows network file system. Apr 11, 2025 · Learn what the SMB default port is, the differences between ports 445 and 139, and how SMB communicates over TCP and UDP. Nov 27, 2025 · Learn how the SMB protocol enhances file sharing in Windows Server with features like encryption, performance optimization, and high availability. Both SMB and CIFS are also available on VMS, several versions of Unix, and Nov 8, 2023 · This change enforces a higher degree of default of network security as well as bringing SMB firewall rules closer to the Windows Server “File Server” role behavior, which only opens the minimum ports needed to connect and manage sharing. Their network setups relied on a netbios server (WINS) [Windows Internet Naming Service] to providing the naming to pass to the clients. 0. Jan 3, 2012 · Ports 137-139 are for NetBios/Name resolution. Server Message Block (SMB) enables file sharing, printer sharing, network browsing, and inter-process communication (through named pipes) over a computer network. SMB operates over TCP port 445 and enables shared access to files, printers, and serial ports among devices on a network. Jul 3, 2022 · SMB (Server Message Block) # At a Glance # Default Ports SMB over NBT (NetBIOS over TCP/IP): 139 SMB over TCP/IP: 445 SMB is a network communication protocol for providing shared access to files, printers, and serial ports between nodes on a network. Organizations can allow port 445 access to specific Azure Datacenter and O365 IP ranges to enable hybrid scenarios in which on-premises clients (behind an enterprise firewall) use the SMB port to talk to Azure file storage. Sep 27, 2024 · The SMB (Server Message Block) port is a network port primarily utilized for file and resource sharing across a computer network. The Common Internet File System (CIFS) Protocol is a dialect of SMB. Feb 20, 2023 · SMB is the most prevalent protocol for sharing files on Windows. Read up on what will be generally available later in 2024. Mar 16, 2017 · disabling SMBv1 and blocking all versions of SMB at the network boundary by blocking TCP port 445 with related protocols on UDP ports 137-138 and TCP port 139, for all boundary devices. Protect file sharing, prevent unauthorized access, and secure your Windows environment. It also supports Active Directory traffic in many environments, which is why enterprise authentication flows often traverse this port. In this article, we will take a closer look at two specific ports used by SMB: port 445 and port 139. This article examines how Windows file sharing works over ports 445, 139, 138, and 137. SMB provide Nov 1, 2024 · Office 365 URLs and IP address ranges. Mar 17, 2025 · The Server Message Block (SMB) protocol is a client-server communication protocol used for sharing access to files, printers, serial ports and other resources on a network. This guide simplifies the process, empowering you to ensure seamless file sharing and connectivity. SMB uses ports 139 and 445 to facilitate data transmission. Prints information about how Samba was built. Here’s more on how SMB ports work, how they’ve evolved, whether they’re safe and how to address their common vulnerabilities. Perfect for both beginners and advanced users! Mar 16, 2017 · disabling SMBv1 and blocking all versions of SMB at the network boundary by blocking TCP port 445 with related protocols on UDP ports 137-138 and TCP port 139, for all boundary devices. Nov 1, 2024 · Office 365 URLs and IP address ranges. Nov 16, 2025 · Port 445: Functionality and Protocols Involved Port 445 serves Microsoft Windows networks as the native TCP endpoint for Server Message Block (SMB). In other words, WINS was the DNS of its day. Oct 25, 2024 · The SMB client can be used to establish connections with alternative ports for TCP, QUIC, and RDMA. The set of message packets that defines a particular version of the protocol is called a dialect. Among the many ports utilized, SMB ports, particularly Port 445 and Port 139, are pivotal for networking and file sharing. SMB has a sibling called CIFS, which behaves like Samba is a re-implementation of the SMB networking protocol that provides file and print services for various Microsoft Windows clients. It also provides an authenticated IPC (inter-process communication) mechanism. US-CERT cautions users and administrators that disabling or blocking SMB may create problems by obstructing access to shared files, data, or devices. Jul 6, 2025 · SMB is a network file sharing protocol that requires an open port on a computer or server to communicate with other systems. Microsoft's old format for client/server communications was netbios. Sep 11, 2022 · What is SMB The Server Message Block Protocol (SMB Protocol) is a client-server communication protocol that is used on a network to share access to files, printers, serial ports, and data. IBM programmer Barry Feigenbaum developed the Server Message Blocks (SMB) protocol in the 1980s for IBM DOS. 1. Learn more. SMB Port Server Message Block What port does a Samba server use for UDP traffic? SAMBA uses ports 137 – 139 and 445. Master SMB port configuration for network security and learn to protect against cyber threats while enhancing operational safety. Aug 23, 2024 · Many changes are coming to the SMB protocol in Windows 11 and Windows Server 2025. Apr 20, 2022 · The SMB port number is TCP 445. Jun 8, 2020 · To analyze SMB traffic using Wireshark, you can use display filters to focus on specific SMB versions. One of the most fundamental layers of defense for any Linux-based system within an SMB environment is a well-configured firewall. Mar 31, 2017 · How do I configure iptables firewall under CentOS / Fedora / RHEL / Redhat Linux to allow access to the Samba server? How do I open TCP ports # 137, 138, 139 and 445 under Linux so that all Microsoft Windows machine can access files and printer on a Linux host? Jan 12, 2025 · The Server Message Block (SMB) protocol remains one of the most targeted network services during penetration tests and real-world attacks. The default value is taken from the ports parameter in $ {prefix}/etc/smb. 168. Mar 31, 2017 · W hat ports need to be open for Samba to communicate with other windows/linux systems? I need to configure Linux firewall so I need the exact port TCP and UDP port numbers for SMB/CIFS networking protocol. Dec 10, 2022 · Maybe SMB is an even more technical term, but "windows file sharing" or "file sharing in windows", is specific assuming they are using their terminology correctly. As the packet signature is the same for SMB versions 2 and 3, Wireshark uses the display filter smb2 for both SAMBA uses ports 137 – 139 and 445. If you've heard people saying the port number is 139, they could be partially correct. Mar 11, 2025 · See various ways to detect, enable, and disable the Server Message Block (SMB) protocol (SMBv1, SMBv2, and SMBv3) in Windows client and server environments. You can also find related protocols in the file server category. These ports may differ from the default ports assigned by the Internet Assigned Numbers Authority (IANA) and the Internet Engineering Task Force (IETF), which are 445, 443, and 5445 for TCP, QUIC, and RDMA respectively. SMB ports are generally port numbers 139 and 445. For SMBv1, use the filter smb, for SMBv2, use smb2, and for SMBv3, use smb2 && smb2. 0) was originally designed to operate on NetBIOS over TCP/IP , which uses port TCP 139 for session services. For more information, see SMB over QUIC. However, exposing SMB ports without a proper firewall configuration poses significant security risks. Discover how to test SMB connection PowerShell with ease. " Apart from regular resource sharing, SMB is also useful for inter-process communication (IPC), such as in mailslots. In the world of computer networking, ports serve as essential communication endpoints for various protocols and services. Feb 6, 2024 · What is SMB, What is SMB Port Numbers 135 and 445, SMB is a networking protocol that allows systems on a network to share access. . This combination allows file sharing over complex, interconnected networks, including the public Dec 19, 2024 · The SMB is an important subject in contemporary networking since it is used for communication between clients and servers. Without it you will have to access machines by IP address opposed to NetBIOS name. May 22, 2024 · Learn how to seamlessly connect to an SMB share on Windows 11 with our easy-to-follow step-by-step guide. A group at IBM developed the SMB protocol in the 1980s. Microsoft introduced this capability in later versions of SMB starting with Windows 2000, Windows XP and Windows Server 2003. conf The default ports are 139 (used for SMB over NetBIOS over TCP) and port 445 (used for plain SMB over TCP).