Quick Answer: Why Is Port 445 Open?

What ports should be blocked?

For example, the SANS Institute recommends blocking outbound traffic that uses the following ports:MS RPC – TCP & UDP port 135.NetBIOS/IP – TCP & UDP ports 137-139.SMB/IP – TCP port 445.Trivial File Transfer Protocol (TFTP) – UDP port 69.Syslog – UDP port 514.More items…•Oct 16, 2015.

How do I unblock port 445?

To add a firewall rule to allow TCP/445 (SMB/CIFS) and TCP/135 (RPC): 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.

Should I disable SMB?

SMBv1 is an old version of the Server Message Block protocol Windows uses for file sharing on a local network. … If you’re not using any of these applications—and you probably aren’t—you should disable SMBv1 on your Windows PC to help protect it from any future attacks on the vulnerable SMBv1 protocol.

Is port 445 TCP or UDP?

Along with ports 135, 137 and 139, port 445 is a traditional Microsoft networking port with tie-ins to the original NetBIOS service found in earlier versions of Windows OSes. Specifically, TCP port 445 runs server message block (SMB) over TCP/IP. This is a core means for communication on a Microsoft-based LAN.

How do I check if port 139 is open?

For test the port 139, please try use the IP address of the server, NetBIOS or FQDN. You can use the telnet command or PortQuery tools.

Why is port 445 used?

NetBIOS is an older transport layer that allows Windows computers to talk to each other on the same network. Port 445: Later versions of SMB (after Windows 2000) began to use port 445 on top of a TCP stack. Using TCP allows SMB to work over the internet.

Is SMB port 445 secure?

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. …

What is the purpose of port 443?

Port 443 is used explicitly for HTTPS services and hence is the standard port for HTTPS (encrypted) traffic. It is also called HTTPS port 443, so all the secured transactions are made using port 443. You might be surprised to know that almost 95% of the secured sites use port 443 for secure transfers.

What uses 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.

What is port 445 used for in Windows 10?

Port 445 and port 139 are Windows ports. Port 139 is used for Network Basic Input Output System (NetBIOS) name resolution and port 445 is used for Server Message Blocks (SMB). They all serve Windows File and Printer Sharing. … You may understand port 445 in this way.

Is SMB secure?

The support article defined SMB as “a network file sharing and data fabric protocol” that’s used by various operating systems, “including Windows, MacOS, iOS, Linux and Android.” This SMB traffic can be protected at the firewall level, though.

What is port 139 commonly used for?

The port 139 is used for File and Printer Sharing but happens to be the single most dangerous Port on the Internet. This is so because it leaves the hard disk of a user exposed to hackers.

Should I open port 445?

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.

Should I block port 139?

Inbound connection in port 139 (TCP) is not blocked in Windows firewall. Port 139 is utilized by NetBIOS Session service. … Therefore it is advisable to block port 139 in the Firewall.

Does SMB use UDP?

Direct hosted NetBIOS-less SMB traffic uses port 445 (TCP and UDP).