Please replace 'mail.domain.com' in the example below with your actual domain name.
In Windows open your "command prompt" and type the following command: 'telnet mail.domain.com 25'
- If the port is open you should see a SMTP banner.
- If the port is blocked you will get a timeout or connection error.
For Unix based systems open your terminal or SSH and type: 'telnet mail.domain.com 25'
If Telnet is not installed on your Windows system you can follow these instructions.
- Open Control Panel.
- Click Programs and Features.
- Click Turn Windows features on or off.
- In the Windows Features dialog box, check the Telnet Client check box. Click OK.
The system installs the appropriate files. This will take a few seconds to a minute.
