Port 445 Checks & Troubleshooting (2024)

FAQs

What is the problem with port 445? ›

With SMB over port 445, you can remotely access and sync files over the Internet. But remember that it is not necessarily safe to do so, as this could allow attackers to scan the port and possibly obtain sensitive device information. A better solution is to remotely connect to the network using a VPN and then use SMB.

On the diagnostics page, you can check the status for both ports 445, and 1433, and internet speed. If either 445 or 1433 are blocked you will receive an error when performing the respective test. For internet speed, if you are in an office environment, we recommend a minimum of 50 Mbps each way (Download & Upload).

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.

The cybersecurity risks of TCP 445

Despite its utility, TCP 445's open nature can also be its Achilles' heel, exposing networks to unauthorized access and malicious exploits. Cybercriminals can leverage vulnerabilities in this port to inject malware, ransomware, or carry out Denial of Service (DoS) attacks.

Note that blocking TCP 445 will prevent file and printer sharing, including over apps – if this is required for business, you may need to leave the port open on some internal firewalls or use encryption keys.

Port 445 is a Microsoft networking port which is also linked to the NetBIOS service present in earlier versions of Microsoft Operating Systems. It runs Server Message Block (SMB), which allows systems of the same network to share files and printers over TCP/IP. This port shouldn't be opened for external network.

To test if a given outgoing port is blocked on your network by some malicious middlebox, you can try to telnet into a server that has a service running on that port. In this example, we use portquiz.net--which is a public service designed for this purpose. It uses iptables' nat table and has all tcp ports open.

-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 445, then click Next.

How do you check whether port is running or not? ›

Enter "telnet + IP address or hostname + port number" (e.g., telnet www.example.com 1723 or telnet 10.17.xxx.xxx 5000) to run the telnet command in Command Prompt and test the TCP port status. If the port is open, only a cursor will show. If the port is closed, a message will say Connect failed.

Open a command prompt and type “ipconfig.” Use the IP address and port number to locate an open port. For Mac devices, open a Terminal window. Type “netsat -nr | grep default” into the program. Then, type “nc -vs” + your IP + port number to locate.

Use firewalls to block incoming and outgoing SMB traffic from external sources. This measure is particularly important for port 445, which should never be accessible from the internet.

Ports 80, 443, 8080 and 8443 (HTTP and HTTPS)

As the most popular internet protocols, HTTP and HTTPS tend to be targeted by malicious actors. Their actions often involve SQL injections, cross-site scripting, DDoS attacks, and request forgery.

To find open ports on a computer and to check what application is using specified port, use the netstat command line: Open the command prompt (Start > Run > cmd) and use netstat -ano | find /i "<port_number>". It will show you all processes that use the specified port. Notice the PID (process id) in the right column.

Port 445 is used by newer versions of SMB (after Windows 2000) on top of a TCP stack, allowing SMB to communicate over the Internet. This also means you can use IP addresses in order to use SMB like file sharing.

The remote computer isn't responding to connections on port 445, possibly due to firewall or security policy settings, or because it might be temporarily unavailable. Windows couldn't find any problems with the firewall on your computer.

Port 139: SMB originally ran on top of NetBIOS using port 139. 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.

-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 445, then click Next.