Windows port 139. Generally favored over port 139, it also allows for communication across different networks for things like internet-based file sharing. Port 139 is primarily used for file and printer sharing services in Windows networks, particularly in versions of Windows prior to Windows 2000. I enabled port forwarding from my router on port 139. 3 I have a samba share, and the network my devices are on blocks communication over port 445 (the standard SMB TCP port). We have received recommendation to not use default ports 139 and 445 (SMB) . In earlier versions of Windows Server, when you created a share, the firewall automatically enabled certain rules in the File and Printer Sharing group. Name Service For a device to participate in a NetBIOS network, it must have a unique name. Jul 6, 2025 · What are Ports 139 and 445? SMB is a network file sharing protocol that requires an open port on a computer or server to communicate with other systems. Apr 14, 2022 · The default dynamic port range for TCP/IP has changed in Windows Vista and in Windows Server 2008 – Windows Server | Microsoft Docs How to configure RPC to use certain ports and how to help secure those ports by using IPsec (microsoft. SMB ports are generally port numbers 139 and 445. It operates as an application layer network protocol for device communication in Windows operating systems over a network. This videos show step by step how to exploit a target machine using an obtained IP address and the open port 139/445 SMB. The official service name for port 139 is ‘netbios-ssn,’ and the port number is registered with the Internet Assigned Numbers Authority (IANA). Even though NetBIOS was developed in the 1980s, amazingly, you can still see that it is alive and well in Windows 10 today. The identification and location of software applications operating on a NetBIOS network are achieved through their NetBIOS names SMB (Server Message Block) is the cornerstone of file and printer sharing in Windows environments. NetBIOS is an older transport layer that allows Windows computers to talk to each other on the same network. The answer contains, "TCP Port 139 and UDP 138 for File Replication Service between domain controllers" This invalidates the entire answer as it does not address the question DC to client and not DC to DC which is different. NetBIOS è un vecchio livello di trasporto che permette ai computer Windows di comunicare tra loro sulla stessa rete. In today’s cloud-first world, especially when deploying on platforms like Cyfuture Cloud, this understanding isn't optional—it's essential. May 15, 2018 · Find answers to Port 139 Blocked on Windows 10 PC from the expert community at Experts Exchange Jul 14, 2023 · Metasploitable 2: Ports 139, 445 This is part V of the Metasploitable 2 series. What do we need so many ports for?! Jan 3, 2012 · If I want to allow Windows networked drives between two firewalled computers, do I need to open ports 137-139, or is port 445 sufficient? I have to submit a form and get approval to open firewall p Contribute to spvreddy/metasploitable-solutions development by creating an account on GitHub. Sep 27, 2021 · Use FILESTREAM in a firewall-protected environment by opening the Windows file-sharing ports 139 and 445 to configure the firewall for FILESTREAM access. Apr 20, 2022 · The SMB port number is TCP 445. Sep 19, 2023 · SMB utilizza la porta IP 139 o 445. Nov 14, 2018 · Can any one please help us to understand Does CPM going to communicate with Windows Server on port TCP 445, 139 for password change? 14 I just wanted to add that for versions of Windows from Windows 2000 and onward, all of the legacy NetBIOS functionality from ports 137, 138 and 139 is by default handled by SMB (Server Message Block) over port 445. That was my problem. Feb 10, 2021 · TCP and UDP Port 53 for DNS from client to domain controller and domain controller to domain controller. Infamous exploits like EternalBlue demonstrate just how SG Ports Services and Protocols - Port 139 tcp/udp information, official and unofficial assignments, known security risks, trojans and applications use. Dec 30, 2016 · In fact, in that case you made need TCP ports 137-139 open. In the world of computer networking, ports serve as essential communication endpoints for various protocols and services. Conclusion Understanding how Windows RPC ports work—specifically 135, 137, 139, and yes, even Port 145—can dramatically improve how you manage your network and its security. However, I literally typed your question, "Why does my windows DC try connect to port 389, 445, 139 of the clients?" into Google and the second link provided all the answers: Which ports should be open from Domain Controller to Client UDP Port 389 for LDAP to handle normal queries Apr 20, 2022 · Over 700,000 Microsoft machines could be exposed. I understand that previously Port 139 was more popular with ol Effect of changes Blocking connectivity to SMB might prevent various applications or services from functioning. 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 Jan 14, 2025 · This page provides an overview of the ports scanned by Lansweeper, including ports used for internal communication between Lansweeper components and ports used for communication with scanned devices. Learn what runs on this port, security risks, and best practices. I would recommend disabling it only after ensuring you know that the machine's in question aren't depending on it. Operating over TCP, this port allows clients to connect to SMB services provided by servers, enabling functionalities such as file sharing and network resource Oct 13, 2021 · Session services —TCP port 139 provides the communication channel, allowing two computers to communicate. A File Services Best Practices Analyzer scan reports that firewall ports necessary for file and printer sharing aren't open (ports 445 and 139). Oct 7, 2020 · Modern Windows versions rely on port 445 for SMB traffic, making it a critical component of contemporary network architectures. As you can perceive we are sharing Apr 17, 2020 · Working ports below: Port 135 – Remote Procedure Call (RPC) Port 137 – NetBIOS Name Service Port 138 – NetBIOS Datagram Service Port 139 – NetBIOS Session Service Information that can be gained includes (but not limited to): Users and groups / shares Operating system information Password policies / Password hashes Privileges / Permissions Jun 17, 2020 · Enumeration Cheatsheets Enumerating SMB, RPC, and NetBIOS for Pentesting (Ports 445, 135-139) Posted on June 17, 2020 by Harley in Enumeration Cheatsheets Nov 14, 2024 · To demonstrate how to exploit the SMB (Server Message Block) service running on port 139 of Metasploitable 2, showcasing user enumeration, potential access to shared resources, and leveraging Port 139 shouldn't be opened on any machine unless there is a business need in opening it at both the local firewall and the VLAN. Oct 20, 2023 · What is Port 139? by Colin Cohen | Published on October 20, 2023 Port 139 is a dedicated port for providing session services for the Server Message Block (SMB) protocol over NetBIOS, which is primarily used for sharing printers and files in a Windows-based network. The last remote exploits that targeted NetBIOS/139 were in the Windows NT/2000 day to the best of my I don't usually like to knock people on here, because at some point or another we were all new and all learning. NetBIOS is a service on the Open Systems Interconnection (OSI) model’s session layer that allows applications to communicate with one another within a local area network (LAN). 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. Session service for connection-oriented communication (port: 139/tcp). Feb 16, 2025 · TCP Port 135 is used by Windows RPC services to tackle core functionalities. At the same time, I will also explain how to disable the old TCP port 139. See which machines are most vulnerable to CVE-2022-26809 MS-RPC vulnerability. TCP and UDP Port 445 for File Replication Service TCP Port 3268 and 3269 for Global Catalog from client to domain Apr 14, 2022 · 3 - Impact and Mitigation If you made it this far, you probably already subscribed to the idea of closing ports 135/139/445 on your firewall. Many system administrators diligently filter access to ports between 135 and 139, but have been known to neglect port 445 when protecting Windows 2000 hosts. If left unchecked, it can lead to disastrous security problems. The same From Wikidepia: Name service for name registration and resolution (ports: 137/udp and 137/tcp). This comprehensive guide covers common attack vectors, signs of SMB attacks, firewall configurations, network segmentation, and the critical need for regular software updates. For a list of Windows and Windows Server applications and services that may stop functioning in this situation, see Service overview and network port requirements for Windows More information Perimeter firewall approaches Feb 8, 2024 · Datagram distribution service for connectionless communication (port: 138/udp). Nov 10, 2024 · What is Port 139? Port 139 is a TCP port in the Windows operating system associated with the NetBIOS Session Service. If you've heard people saying the port number is 139, they could be partially correct. Jan 15, 2025 · A roadmap of ports, protocols, and services that are required by Microsoft client and server operating systems, server-based applications, and their subcomponents to function in a segmented network. Open any host firewalls to allow connections from Tenable Nessus to File and Printer Sharing on TCP ports 139 and 445. I will explain the role of this port and its relationship with Windows security. This is so because it leaves the hard disk of a user exposed to hackers. Enabling NetBIOS services provide access to shared resources like files and printers not only to your network computers but also to anyone across the internet. Hence my concern is that, is there a way to close these open ports and please let me know why these ports were opened (is it due to malware) A quick response is highly appreciated in this regard. Datagram distribution service for connectionless communication (port: 138/udp). However, temporarily turning off the firewall as I suggest will tell you if it is a port/firewall issue. It usually runs on port 445, though older versions may use port 139. File and Print Sharing opens: tcp/135, tcp/445, tcp/139, tcp/5985. Feb 20, 2023 · SMB is the most prevalent protocol for sharing files on Windows. Server 2016 DCs have tcp/139 open as well as tcp/137. 20 Ports are not vulnerable, they are just ports. Among the many ports utilized, SMB ports, particularly Port 445 and Port 139, are pivotal for networking and file sharing. Can you provide me a list of ports along with sample iptables rules? You can get list of ports from file called /etc/services. Remember always test the default Windows credentials for old systems. Windows 2000 and later support Common Internet File System (CIFS), which provides full SMB access directly through TCP and UDP port 445 (as opposed to using a variety of UDP and TCP ports). Can we use an alternative port in place of 139 and 445 for sql logshipping and network file transfer . Question - if the… Nov 15, 2022 · Hello I received the following reply from the security team while checking the Active Directory server firewall. Dec 13, 2024 · Windows 11 24H2 and Server 2025 improve the SMB protocol with a strong focus on security. In general, you should only allow ports open that are in use vs. Removing the NetBIOS transport has several advantages, including: Simplifying the Aug 10, 2012 · Net use stops working after joining Domain. Port 139 The Network Basic Input Output System ** (NetBIOS)** is a software protocol designed to enable applications, PCs, and Desktops within a local area network (LAN) to interact with network hardware and facilitate the transmission of data across the network. SMB 1. Additionally, discover how to use Intrusion Detection and Prevention Systems (IDPS) effectively Mar 26, 2021 · Discover the basics around SMB protocol, port 445 and 139 and differences. Let’s understand the SMB ports 445, 139, 138, and 137 in detail. In this article, we will take a closer look at two specific ports used by SMB: port 445 and port 139. Port 139 is used by SMB dialects that communicate over NetBIOS. . Active Directory Domain Controllers (DCs) use ports for communication and data transfer and the most common protocols are Jul 5, 1997 · Windows port 139 (NetBIOS) is most susceptible to this attack. Microsoft introduced TCP port 445 in Windows 2000, and it is still used in Windows 10 and Windows Server 2019. 0) was originally designed to operate on NetBIOS over TCP/IP , which uses port TCP 139 for session services. When a computer connects to another computer over a network to access shared files, folders, or printers, the session is often established via Port 139. Port 139: SMB originally ran on top of NetBIOS using port 139. With a normal explorer (explorer. Security: Port 139 is frequently targeted for SMB null-session enumeration, SMB credential brute-forcing, and MS08-067 (Conficker) exploitation of the Windows Server service reachable over 139/445. The transition from port 139 to 445 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. May 31, 2024 · When managing passwords for local accounts on Windows servers, the CPM relies on Windows protocols (SMB, RPC, WMI, DCOM) over ports 139 and 445. Porta 445: le versioni successive di SMB (dopo Windows 2000) hanno iniziato ad usare la porta 445 sopra uno stack TCP. TL;DR Service: NetBIOS Session Service Risks: Unauthorized access, information disclosure Mitigation: Disable NetBIOS over TCP/IP if not needed, restrict Nov 3, 2024 · Learn about the importance of securing Port 139 and the vulnerabilities associated with Server Message Block (SMB) protocol. SMB, or Server Message Block, protocol is mainly used for sharing printers and files within a Windows-based network. US-CERT cautions users and administrators that disabling or blocking SMB may create problems by obstructing access to shared files, data, or devices. Under Windows NT, SMB is run through NetBIOS over TCP/IP, using UDP ports 137 and 138 and TCP port 139. Complete List of Active Directory Ports and What They Do Explained. Rebooting the affected machine is required to resume normal system functioning. Jul 19, 2017 · I can access them using the web interface but not using Windows Explorer So i digged into this a little bit and found out that the smb ports 139 and 445 are not listening Dec 10, 2024 · WannaCry ransomware run amuck recently. The question is between DC and client. Read about whether SMB is secure and how to protect against dangerous attacks. Jan 16, 2023 · Port 139 is used by SMB dialects that communicate over NetBIOS. I connect via the File Explorer by mapping a network drive. Also, understand how to check open ports on Windows, Mac, etc Jan 15, 2025 · Provides a solution to an issue where Server Message Block (SMB) sharing is not accessible when TCP port 445 is listening in Windows Server. 2008R2 DCs do not. This port facilitates network communications, allowing computers to share files, printers, and serial ports over a network. Therefore it is advisable to block port 139 in the Firewall. Jan 2, 2025 · Hello team , We use windows 2012 R2 and windows 2019 servers in our environment . Jul 29, 2021 · Learn what is the use of TCP port 445 in Windows and how to disable or block iport 445 in Windows 7/10 or 11 using command prompt. For Port 139, utilized by the SMB protocol, enables file and printer sharing on Windows networks, requiring secure configuration. With Windows 2000, Microsoft added CIFS support, which provides full SMB access directly through TCP and UDP port 445 (as opposed to using a variety of UDP and TCP ports). And port 445 which is for Windows File Sharing is vulnerable as well. Port-135, as mentioned earlier, is associated with the RPC Endpoint Mapper service that allows systems to discover available services on a remote machine. Nov 8, 2023 · In this post we will look at some tools we can use to enumerate the NetBIOS and SMB services utilizing UDP ports 137 and 138 as well as TCP ports 139, and 445. In part I the lab was prepared, in part II we tested port 21, in part III we tested port 25, in part IV it was port Port 139 is used for netbios-ssn, a This service provides session services for NetBIOS over TCP/IP networks, enabling applications to establish connections and share resources. If you have old clients in your network, the earlier version of SMB (SMB 1. In this article we will firstly introduce what is Active Directory (AD) is and how it functions. It uses TCP ports 139 and 445 by default. Through computer > properties, the user can view basic information about their computer. Oct 9, 2021 · An active directory port is a TCP or UDP port that services requests to an active directory domain controller. The end of the video shows how to remove a password stored in Mar 4, 2025 · By default, SMB relies on port 139 (NetBIOS) or port 445 (TCP) to allow mapped drive access. The actual share access is done via TCP port 445 (since Windows 2000!) and if you will only access the machine via IP then that is the only port that will be used. Jan 15, 2025 · Windows supports file and printer-sharing traffic by using the SMB protocol directly hosted on TCP. Beginning with Windows 11, version 24H2 and Windows Server 2025, the built-in firewall rules doesn't contain the SMB NetBIOS ports anymore. After joining domain computer started to use 139 instead of 445 for smb. Nov 7, 2024 · Port 139, primarily used by the Server Message Block (SMB) protocol for file sharing in Windows networks, stands out as a critical point of vulnerability when not properly secured. An attacker may use NetBIOs to perform an attack on Port 139 and 445, learn how to find and fix this vulnerability. Feb 25, 2021 · Hello! Each client computer can act as an SMB server and a client. It is used for file and printer sharing over a network using the Server Message Block (SMB) protocol. Sep 27, 2024 · Port 445 port is used by newer versions of SMB as Windows 2000 adopted it for use for direct TCP/IP communication. In Windows NT it ran on top of NBT (NetBIOS over TCP/IP), which used ports 137, 138 (UDP) and 139 (TCP). Administrator: <BLANK> SID 5000 is admin account NetBIOS Hacking Tools Feb 25, 2025 · Port-135 and port 139 serve different purposes in networking. Worked on computer before joining domain. This port is commonly used by Windows operating systems for network communication. May 2, 2025 · The following tables describe network ports that must be opened to ensure proper communication of components in the Veeam Agent management infrastructure. Dec 12, 2022 · TCP/UDP port 137-139: Ports 137, 138, and 139 are all used for providing different features relating to SMB protocol over NetBIOS. Prior to Windows 2000, most operating systems used TCP 139, with SMB running on top of NetBIOS. com) The RPC endpoint mapper can be accessed via TCP and UDP port 135, SMB on TCP 139 and 445 (with a null or authenticated session), and as a web service on TCP port 593. Use proper authentication and share permissions. UDP Port 88 for Kerberos authentication TCP Port 139 and UDP 138 for File Replication Service between domain controllers. What is Port 139? Port number 139 is associated with the Server Message Block (SMB) protocol over NetBIOS, which facilitates shared access to files, printers, and serial ports in a networked environment, particularly in Windows systems. 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. Under Windows Firewall > Windows Firewall Settings, enable File and Printer Sharing. Ports those registered with IANA are shown as official ports. Dangerous ports: netbios 135, 137, 138, 139, 445 and 25 details tcp/udp 445, 135 tcp25, 139 UDP 137, 138, 139 I… May 13, 2023 · 2 I am trying to connect to a network drive being hosted on a Windows Server 2022 from my Windows clients on different networks. But blocking SMB traffic internally is more tricky. I'm also trying to discover the relationship between netbios-ssn typically running on Port 139 and microsoft-ds running on Port 445. Port 135 Port 137 Port 139 Higher ports that are published by Port 135's "catalog" Then I heard that Port 145 came into the mix to "make things better" with NBT/TCP but I'm not sure how this fits in with the sequence of a Windows client initiating an RPC action. In Windows 2000, Microsoft added the possibility to run SMB directly over TCP/IP, without the extra layer of NBT. Port 139 is utilized by NetBIOS Session service. One key feature is the ability to change ports to TCP 445, which offers enhanced security and flexibility. If the 'VerifyMachineNameBeforeAction' parameter is set to 'Yes,' an additional port, 135 (dynamic port range), is used. blocking specific "dangerous" ports (expectations are ISPs and likely some Universities). 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. The issue prevents computer access to shared folders and other SMB-based network services on the server. exe) we can normally get shared resources by connecting to the target server at \\server. It is important to know how to block/disable/close TCP port 445, 135, 139 opened by system on Windows 7, 10, 11, Server 2003 and 2008 step by step. How does SMB Protocol work? Client-Server Communication SMB is known as a response-request Oct 3, 2023 · Port 139 is used for File and Printer Sharing but is the single most dangerous Port on the Internet. Communication Between Veeam Backup & Replication. 2, requires TCP/IP over port 445. Linux devices and Macs can connect to this device because they can communicate with the server using port 139 (NBT over IP), which is not blocked Windows devices, however, seem to insist they communicate over port 445. Jun 23, 2022 · The answer is not provided. Sep 7, 2017 · From the result of scanning, you can observe that after sharing a folder we found port 135, 139 and 445 get activated. Because SMB is so deeply woven into many networks, it often goes unnoticed, making it a treasure trove for attackers looking to gather information or move laterally. 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. 0. Porta 139: SMB originariamente funzionava sopra NetBIOS usando la porta 139. However, it can also be used by malware to spread and infect other computers on the network. Modern SMB prefers 445 (direct hosting), but 139 remains present in many legacy Windows and Samba/NAS environments. Even though this solution didn't work for me, it leads me in the right direction. This article examines how Windows file sharing works over ports 445, 139, 138, and 137. The name Samba comes from SMB (Server Message Block), the name of the standard protocol used by the Microsoft Windows network file system. although other services may suffer as well. Can anyone help me fix my understanding of RPC ports once and for all? Apr 9, 2021 · As far as I know, port 135 and port 139 pertaining to NetBios are vulnerable. However, this capability is restricted to the QUIC transport on the server side. Jul 31, 2025 · Port 139 Port 139 is used by the NetBIOS session service. To show if you have reserved ports: netsh int ipv4 show excludedportrange protocol=tcp To disable reserved ports reg add HKLM\SYSTEM Apr 1, 2025 · Learn the steps to Open Ports in Windows Firewall on multiple platforms. Jul 19, 2024 · How to protect port 139 from attacks To find listening ports on a computer, run the netstat -aon command on a Windows machine or netstat -tunpl on a Linux variant. Below is an overview of ports scanned by Lansweeper on client machines and ports used for internal May 5, 2023 · Port 139 is known as NetBIOS Session Service. May 15, 2019 · Learn how Windows uses TCP ports 139 and 445 for file sharing and SMB protocol, and how to disable or enable them depending on your needs. Find out the differences between Windows versions and the security implications of null sessions. Jan 14, 2025 · This page provides an overview of the ports scanned by Lansweeper, including ports used for internal communication between Lansweeper components and ports used for communication with scanned devices. I found this link where states about an issue following Windows 10 update 1809 where Windows would reserve a range of ports that included port 50,000. Hence only by sharing a single folder in the network, three ports get opened simultaneously in the target system for communication with another system. Some Notes Standalone Windows 7/10 used the "Public" location when prompted. The clients are Windows 10 Home and Windows 11 Home PCs respectively. This article explores the SMB port in-depth, including its security challenges, emerging protocol enhancements like SMB/QUIC, and recommended alternatives for secure remote access. 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. Services that listen on particular ports may have remotely exploitable vulnerabilities, or misconfiguration of services that listen on particular ports may lead to unintended consequences. Real-Life Example Port 139 has been a favorite target for ransomware, worms, and lateral movement in Windows environments for over two decades. Free port scanning tools, such as Nmap and Netcat, can also detect open ports. This article provides design guidance for which ports and protocols need to be allowed for Operations Manager to communicate through network firewalls and proxy servers. 5bz 3cyn0zc cpjdg bgmt bgqqxy 0eqb svq m3oj ig8509ow6 wx894