Cannot create UdpPort for specified LocalHost and LocalPort

I want to receive Ethernet data through udpport，It was up and running yesterday。

u=udpport("LocalHost","192.168.33.30","LocalPort",4098,"OutputDatagramSize",65507);

Unable to bind to LOCALHOST and LOCALPORT. Verify that the LOCALPORT is not in use, and that LOCALHOST and LOCALPORT are valid for IPADDRESSVERSION "IPV4".
See related documentation for troubleshooting steps.

Now when I run it, I get an error：

ERROR: Unable to bind to LOCALHOST and LOCALPORT. Verify that the LOCALPORT is not in use, and that LOCALHOST and LOCALPORT are valid for IPADDRESSVERSION "IPV4".

I change different localport and localport，and I even restarted the computer, but still reported the error,I checked the port through cmd and there was no process。I hope to get an answer。

Answer 1

[Sameer]

Hi Jiahao

From my understanding, you want to receive Ethernet data through a UDP port. However, you are facing "Unable to bind to LOCALHOST and LOCALPORT" error.

Here are some steps to troubleshoot and resolve the issue:

1. Verify Localhost and Localport

Ensure that LOCALHOST and LOCALPORT values are correct and not already in use by another application.

Check for Port Usage

Open Command Prompt and run:

netstat -aon | findstr :4098

If the port is in use, it will show up in the list. If it doesn't show up, the port is free.

2. Check Firewall Settings

Ensure that your firewall settings are not blocking the port. You may need to create an inbound rule to allow traffic through the specified port.

3. Verify Network Configuration

Ensure that your network configuration is correct and that the IP address 192.168.33.30 is reachable from your machine.

4. Use a Different Port

Try using a different port number. Sometimes, ports can be reserved or used by the system even if they don't show up in netstat.

5. Run with Administrative Privileges

Try running your application with administrative privileges to ensure it has the necessary permissions to bind to the port.

6. Update or Reinstall Network Drivers

Outdated or corrupted network drivers can cause binding issues. Ensure your network drivers are up to date.

7. Test with Another Tool

Use another tool like netcat or Wireshark to test if you can bind to the port and receive data.

Example Using netcat

To test with netcat, open Command Prompt and run:

nc -l -u -p 4098

This command will listen for UDP traffic on port 4098. If it works, the issue might be with your code or environment setup.

I hope this helps!

Sameer