SMTP Port 587 vs 465: Which Port Should You Use?

The text discusses the differences between SMTP ports 587 and 465, emphasizing the recommendation to use port 587 with StartTLS as the current standard for email client submission due to its flexibility and widespread support. Port 587 supports both secure and non-secure connections, making it more compatible across various environments and email providers, including Gmail and Outlook. In contrast, port 465 uses implicit TLS, which can lead to compatibility issues and is typically used only when port 587 is blocked or for legacy systems. The text highlights that while both ports can be equally secure, the choice of port depends on specific needs and configurations, advising against the use of port 25 for client applications due to its vulnerability to spam and lack of required authentication. Additionally, port 2525 is mentioned as an unofficial alternative when standard ports are blocked. The overall guidance is to prioritize correct authentication and encryption settings over the specific port choice to ensure secure email transmissions.