How do I block access to ports?
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- Click “Start | Control Panel | System and Security | Windows Firewall.”
- Select “Advanced Settings.” Click “Inbound Rules” to block an inbound port; click “Outbound Rules” to block an outbound port.
- Select “New Rule.” Choose “Port” from the options and then click “Next.”
How do I close a port on my router?
The best solution is to close unused ports via the router itself. Make sure your network is operating properly and that you set aside your router’s IP address, password, and network name. Head into the settings page or admin panel and turn off your desired router ports, making sure to save your changes.

What ports should I block on my router?
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.
How do I block ports in Windows 10?
28 Answers
- Open up cmd.exe (note: you may need to run it as an administrator, but this isn’t always necessary), then run the below command: netstat -ano | findstr : (Replace with the port number you want, but keep the colon)
- Next, run the following command: taskkill /PID /F. (No colon this time)
How do I close port 23?

You can stop the service doing the following (Click Start -> Run -> services. msc) and disable it from there. Or with the use of a 3rd party firewall, Such as Online Armor, ZoneAlarm, or Comodo Firewall.
How do I stop port 21?
Open the advanced settings. To the left of the screen should be a menu, click on the advanced settings button. Under “exceptions” find Port 21. It will be listed as open. Remove the exception and restart your computer.
Should I block port 23?
Please block Port 23 and make sure Telnet services are disable. Port 139 – Used by NetBIOS Session Services. Among other things this port is vulnerable to Null session attacks, where an attacker can connect to the Windows IPC share without valid user credentials, and then gain access to other parts of the server.
Can I block port 135?
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.
What are the disadvantages of UDP port 8883?
UDP port 8883 would not have guaranteed communication as TCP. UDP on port 8883 provides an unreliable service and datagrams may arrive duplicated, out of order, or missing without notice.
What is Port 8883 used for?
Port 8883 Details. Dynamic/Private : 49152 through 65535. TCP ports use the Transmission Control Protocol. TCP is the most commonly used protocol on the Internet and any TCP/IP network. Whereas the IP protocol deals only with packets, TCP enables two hosts to establish a connection and exchange streams of data.
How do I troubleshoot unknown open ports?
When troubleshooting unknown open ports, it is useful to find exactly what services/processes are listening to them. This can be accomplished in both Windows command prompt and Linux variants using the “netstat -aon” command. We also recommend runnig multiple anti-virus/anti-malware scans to rule out the possibility of active malicious software.