Which SMTP Port to Use? Understanding ports 25, 465, & 587

It’s a common question that we receive here at Sinch Mailgun about SMTP port numbers . To ensure connectivity to our Simple Mail Transfer Protocol (SMTP) endpoint, Mailgun offers multiple SMTP port options , but which one should you use to send email messages? We’ll take a historical look at each SMTP port and then we’ll discuss today’s methodology for outgoing mail usage. If you’re not a history buff, go to “Today’s Usage” for the most common SMTP ports. Table of contents 01 What is SMTP?…