Free telnet server for testing
![free telnet server for testing free telnet server for testing](https://networkinterview.com/wp-content/uploads/2019/06/WHAT-IS-TELNET.jpg)
At SocketLabs, we support ports 25, 2525, and 587. For example, if your ISP is blocking port 25, then try a different port, such as 2525 or 587. If you find that your SMTP connection issue is not the result of your antivirus software or firewall, then the next step is to ensure that your Internet Service Provider allows for SMTP transmission on the SMTP port that you’re using.
![free telnet server for testing free telnet server for testing](http://woshub.com/wp-content/uploads/2017/12/Basic-Authentication-exchange.jpg)
If that works, it means that you need to update your firewall settings. If you think that your firewall is stopping your mail from sending via SMTP, then try turning it off and reconnecting.
![free telnet server for testing free telnet server for testing](https://cdn.goengineer.com/SOLIDWORKS-PDM-–-Test-Port-Communication-using-Windows-Telnet-feature-2-300x262.png)
In addition to antivirus software, firewalls are another common cause of SMTP connection issues. If this works, then you know that you’ll need to make changes to your antivirus software. To see if your antivirus software is the issue, try disabling the software and connect to your SMTP relay server again. While this security feature is extremely important, it can sometimes block email and cause connection issues. In an older, but still relevant blog post titled: Diagnosing SMTP Service Connection Issues, we break down some of the root causes for SMTP connection problems - but we’ve summarized them here: 1) Antivirus SoftwareĪ first step in troubleshooting an SMTP server connection issue is to take a look at your antivirus software. SMTP Not Sending: 4 Common Causes of SMTP Server Connection Issues