What ports need to be open for SMB? (2024)

What ports need to be open for SMB?

SMB ports (especially 445) are needed for file sharing (even between Windows and Linux, with the so-called Samba shares).

Which ports need to be open for SMB?

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.

Is port 445 enough for SMB?

Yes, modern SMB (especially v2/v3) runs only on TCP port 445. However, Windows clients may also expect the server to be pingable, i.e. respond to ICMP Echo, before they even attempt a SMB connection.

What port is SMB share?

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.

What ports should always be open?

Is port 445 open by default?

If the server has NBT enabled, it listens on UDP ports 137 and 138, and TCP ports 139 and 445. If it has NBT disabled, it listens on TCP port 445 only. All four ports are open as default in all versions of Windows, including Windows 10 and Windows Server 2019.

What is 445 port used for?

Port 445 is a traditional Microsoft networking port with tie-ins to the original NetBIOS service found in earlier versions of Windows OSes. Today, port 445 is used by Microsoft Directory Services for Active Directory (AD) and for the Server Message Block (SMB) protocol over TCP/IP.

How do I know if SMB port 445 is open?

If we want to check the ports 137,138,139 and 445 whether they are open we can use netstat command. This list open ports with TCP and UDP protocols. As we can see from the example the TCP 445 is open and listening mode which means this system will accept connections to the 445 port.

How do I test my SMB port?

To identify ports and network interfaces your Samba domain member is listening on, run: # netstat -tulpn | egrep "smbd|nmbd|winbind" tcp 0 0 127.0.

Should port 445 be blocked?

We also recommend blocking port 445 on internal firewalls to segment your network – this will prevent internal spreading of the ransomware. Note that blocking TCP 445 will prevent file and printer sharing – if this is required for business, you may need to leave the port open on some internal firewalls.

How do I enable SMB port 445?

Go to Computer Configuration > Policies > Windows Settings > Security Settings > Windows Firewall with Advanced Security > Windows Firewall with Advanced Security - LDAP > Inbound Rules. Right-click and choose New Rule. Choose Port and click Next. Choose TCP and at specific local ports enter 135, 445, then click Next.

Does SMB use TCP or UDP?

SMB relies on the TCP and IP protocols for transport. This combination potentially allows file sharing over complex, interconnected networks, including the public Internet. The SMB server component uses TCP port 445.

What ports do SMB and CIFS use?

Which ports should be blocked?

Is port 443 always open?

Is port 443 suppose to be open by default in windows 8.1 pro? The answer is no.. To open a port, a process/application should be installed and configured to listen to port 443.. Typically if you are using a web server with https/teamviewer/skype there is possibility to see 443 port is opened..

What ports should always be closed?

Is SMB port 139 TCP or UDP?

The earlier version of SMB (SMB 1.0) was originally designed to operate on NetBIOS over TCP/IP (NBT), which uses port TCP 139 for session services, port TCP/UDP 137 for name services, and port UDP 138 for datagram services.

Does SMB require UDP?

Windows supports file and printer-sharing traffic by using the SMB protocol directly hosted on TCP. SMB 1.0 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. 2, requires TCP/IP over port 445.

What is SMB protocol?

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.

Should I block port 443?

You should not block outgoing traffic to TCP:443, but only incoming.

Should port 21 be closed?

The protocol contains well-known design flaws that can be used by attackers. This port should be blocked. Port 21 – Used by FTP to allow file transfers. Most hosts on your network are not intended to be FTP Servers - don't leave doors open that don't need to be open.

Should I open port 22?

Aspera recommends opening TCP/33001 and disabling TCP/22 to prevent security breaches of your SSH server. To enable TCP/33001 while your organization is migrating from TCP/22, open Port 33001 within your sshd_config file (where SSHD is listening on both ports).

What is port 8080 typically used for?

Port number 8080 is usually used for web servers. When a port number is added to the end of the domain name, it drives traffic to the web server. However, users can not reserve port 8080 for secondary web servers.

Is port 8080 secure?

Is port 8080 a secure port? Ans: We can't tell whether the port is secure or not just by looking at it. As a result, either port 80 or 8080 is insecure by default. To secure the port, we must add an SSL certificate.

What are ports 80 and 443 used for?

Port-443 allows data transmission over a secured network, while Port 80 enables data transmission in plain text. Users will get an insecure warning if he tries to access a non-HTTPS web page. Port 443 encrypts network data packets before data transmission takes place.

What ports are blocked on my network?

Why is port 443 secure?

HTTPS is secure and is on port 443, while HTTP is unsecured and available on port 80. Information that travels on the port 443 is encrypted using Secure Sockets Layer (SSL) or its new version, Transport Layer Security (TLS) and hence safer.

What are common ports?

Does SMB use TCP or UDP?

SMB relies on the TCP and IP protocols for transport. This combination potentially allows file sharing over complex, interconnected networks, including the public Internet. The SMB server component uses TCP port 445.

What are ports 137 and 138 used for?

UDP ports 137 and 138 are used for local NetBIOS browser, naming, and lookup functions.

Is port 445 TCP or UDP?

TCP port 445 is used for direct TCP/IP MS Networking access without the need for a NetBIOS layer. This service is only implemented in the more recent verions Windows starting with Windows 2000 and Windows XP. The SMB (Server Message Block) protocol is used among other things for file sharing in Windows NT/2K/XP.

What happens if I block port 445?

Blocking TCP 445 will prevent file and printer sharing and also other services such as DHCP (dynamic host configuration protocol) which is frequently used for automatically obtaining an IP address from the DHCP servers used by many corporations and ISPs(Internet Service Providers) will stop functioning.

Is SMB port 139 TCP or UDP?

The earlier version of SMB (SMB 1.0) was originally designed to operate on NetBIOS over TCP/IP (NBT), which uses port TCP 139 for session services, port TCP/UDP 137 for name services, and port UDP 138 for datagram services.

Does SMB require UDP?

Windows supports file and printer-sharing traffic by using the SMB protocol directly hosted on TCP. SMB 1.0 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. 2, requires TCP/IP over port 445.

What type of protocol is SMB?

The Server Message Block (SMB) protocol is a network file sharing protocol that allows applications on a computer to read and write to files and to request services from server programs in a computer network. The SMB protocol can be used on top of its TCP/IP protocol or other network protocols.

Is NetBIOS needed for SMB?

SMB does rely on NetBIOS for communication with devices that do not support direct hosting of SMB over TCP/IP. NetBIOS is completely independent from SMB.

What ports do SMB and CIFS use?

Should I open port 139?

If you are on Windows-based network that is running NetBios, it is perfectly normal to have port 139 open in order to facilitate that protocol. If you are not on a network using NetBios, there is no reason to have that port open.

How do I enable SMB port 445?

Go to Computer Configuration > Policies > Windows Settings > Security Settings > Windows Firewall with Advanced Security > Windows Firewall with Advanced Security - LDAP > Inbound Rules. Right-click and choose New Rule. Choose Port and click Next. Choose TCP and at specific local ports enter 135, 445, then click Next.

How can I tell if port 445 is open?

Answer: Open the Run command and type cmd to open the command prompt. Type: “netstat –na” and hit enter. Find port 445 under the Local Address and check the State. If it says Listening, your port is open.

What is SMB directly over IP?

While Port 139 is known technically as 'NBT over IP', Port 445 is 'SMB over IP'. SMB stands for 'Server Message Blocks'. Server Message Block in modern language is also known as Common Internet File System.

What ports should be blocked?

Should you block SMB?

You must not globally block inbound SMB traffic to domain controllers or file servers. However, you can restrict access to them from trusted IP ranges and devices to lower their attack surface. They should also be restricted to Domain or Private firewall profiles and not allow Guest/Public traffic.

Should port 135 be blocked?

Hacker tools such as "epdump" (Endpoint Dump) can immediately identify every DCOM-related server/service running on the user''s hosting computer and match them up with known exploits against those services. Therefore, port 135 should not be exposed to the internet and must be blocked.