telnet gmail-smtp-in.l.google.com 25 HELO mydomain.com MAIL FROM:<test@example.com> RCPT TO:<recipient@gmail.com> DATA Subject: Test This is a test. . QUIT Quickly verify if a firewall is blocking a specific port:
telnet If enabled, you will see the Microsoft Telnet prompt: Microsoft Telnet> Once the client is active, the syntax is: windows telnet
Install-WindowsFeature -Name Telnet-Client Open a new Command Prompt and type: telnet gmail-smtp-in
dism /online /Enable-Feature /FeatureName:TelnetClient Alternatively, using PowerShell (Admin): Once the client is active