How to Block Port 25 on a Windows Firewall

1. Click 'Start,' 'Control Panel,' 'System and Security' and 'Windows Firewall.'
2. Click 'Advanced Settings' in the left sidebar of the Windows Firewall window.
3. Click 'Inbound Rules' at the left side of the advanced firewall settings window.
4. Click 'New Rule' at the right side of the window.
5. Click 'Port' in the wizard window and click 'Next.'
6. Type '25' into the 'Specific Local Ports' box and click 'Next.'
7. Click 'Block the Connection' and click 'Next.'
8. Block port 25 on all network profiles by clicking 'Next.'
9. Type a name for the port-blocking firewall rule into the 'Name' box.
10. Click 'Finish.'