SolidWorks primarily communicates using ports and 25735 . How to open the ports:
or
If your company recently migrated its SolidWorks SolidNetWork License (SNL) Manager to a new server, the old server's IP might still be hardcoded in your hosts file.
Once the file opens, you will see a mix of text lines starting with # symbols (which are notes/comments) and lines with IP addresses. Scroll to the very bottom of the document. Look for lines containing keywords like: solidworks 3ds flexlm ://solidworks.com solidworks host file block fix
file is a common and effective workaround. This bypasses DNS resolution issues by manually mapping a server's IP address to its hostname. GoEngineer 🛠️ Step-by-Step Fix: Modifying the Hosts File
If your hosts file did not contain any blocked entries, the issue may be different:
Highlight all lines referencing SolidWorks server addresses. Press to remove them completely. Step 4: Save and Close Click File and select Save (or press Ctrl + S ). Close Notepad. Step 5: Flush Your DNS Cache SolidWorks primarily communicates using ports and 25735
: If the host file is correct but you still can't connect, ensure TCP ports 25734 and 25735 are open in your Windows Firewall for the SolidNetWork License (SNL) Manager .
Some aggressive antivirus or firewall programs modify the hosts file to block outbound connections, accidentally sweeping up legitimate SolidWorks validation domains.
: Scroll to the bottom and add a new line for each server using the format: [IP Address] [Server Name] . Example: 192.168.1.100 MyPDMVaultServer Save and Close : Save the file. Do not add a .txt extension. Scroll to the very bottom of the document
You should see a confirmation message stating: "Successfully flushed the DNS Resolver Cache." Close the Command Prompt. Troubleshooting Persistent Licensing Issues
Open the Windows menu, type cmd , and select Run as administrator to open the Command Prompt.
Scroll to the very bottom of the file. Start a new line beneath any existing text. Enter the local loopback IP address ( 127.0.0.1 ), press the Tab key, and enter the target licensing domain.