SMTP Port 101: Understanding Ports 25, 465, 587 and 2525
Ever wondered what numbers like 25, 465, and 587 mean in an SMTP port? Learning about these ports and their properties will help you choose the right port.
Don't worry if you're not a tech whiz – we'll break it down in easy-to-understand terms so you can grasp how these numbers make your emails go from one place to another smoothly. Let's get started!
What does SMTP Stand For?
SMTP, which is a Simple Mail Transfer Protocol is a technique that enables emails sending over the server. It's a protocol that is used for the transition of emails from one server to another.
What is an SMTP Port?
An SMTP port is the endpoint of communication that servers use to connect and share information. For example, when you send an email from port A, servers transmit the message to port B using these ports.
The most significant ports include:
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Port 25 (standard port)
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Port 465 (secure port)
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Port 587 (extended security port)
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Port 2525 (alternative of 587)
Let's make it clear that all these ports are used differently for different purposes. Hence, choosing the right port is essential to prevent the sender from any negative consequences.
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What is Port 25?
Port 25 is the default port used for sending email messages via the Simple Mail Transfer Protocol (SMTP). It is the oldest port or the beginning of ports, which is why it is used as the default.
When you send an email from your email client (such as Outlook or Gmail), the email is typically sent to an SMTP server using port 25, which then forwards it to the recipient's SMTP server for delivery.
However, as the technology improved, the usage decreased drastically because many ISPs and hosting providers blocked it. The reason was simple: to prevent spamming over this port.
What is Port 465?
Port 465 is used for sending encrypted messages. It works on the SMTPS, where ‘S’ stands for secure. SMTPS uses Secure Socket Layer (SSL) or Transport Layer Security (TLS). This encryption helps secure sensitive data and information, such as login credentials.
It's worth noting that while port 465 was originally designated for SMTPS, the Internet Assigned Numbers Authority (IANA) has since deprecated its formal designation for this purpose. However, port 465 is still widely used by many email service providers and email clients for secure email transmission.
What is Port 587?
Port 587 is used for email submission, and as a result, almost all mail servers support this port. Further, it supports encryption and authentication. As a result, it ensures and enhances the security of email transactions.
Unlike ports 25 and 465 (which are used for communication between mail servers), port 587 is designed for email clients (Outlook or Thunderbird) for outgoing emails.
However, if you wish to use this port, first check with your hosting services. Many of them may not support port 587.
What is Port 2525?
Port 2525 is an alternative to port 587 and is commonly used for email submission. Unlike other ports, port 2525 is widely supported by most hosting services. Therefore, it is preferred when ports 25, 465, or 587 are restricted or blocked by network administrators or ISPs.
Which Port is Best for Email Marketing?
Email marketers typically use port 587 for sending emails because it's specifically designated for email submission and supports encryption and authentication. Here are some reasons why port 587 is commonly preferred:
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Secure Communication: Port 587 supports encryption through TLS (Transport Layer Security) or SSL (Secure Sockets Layer), which helps protect sensitive information, such as email content and login credentials, from being intercepted by unauthorized parties.
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Authentication: Port 587 often requires authentication before sending emails, which helps verify the identity of the sender. This adds an extra layer of security and reduces the risk of unauthorized use of the email server.
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ISP and Network Compatibility: Port 587 is less likely to be blocked by ISPs or network administrators compared to port 25. Therefore, it provides better compatibility and reliability for sending emails, especially when sending from locations outside the user's trusted network.
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Best Practice: Using port 587 aligns with best practices for email delivery and security. Many email service providers and email clients recommend using port 587 for outgoing email transmission.
Overall, Port 587 offers a balance between security, reliability, and compatibility, making it a preferred choice for email marketers when sending bulk emails or newsletters. Nonetheless, as mentioned earlier, port 2525 is the best alternative for this port when port 587 is restricted or blocked.
Bottom Line
We trust that you'll find our blog on understanding SMTP ports valuable. Knowing these distinctions is crucial for selecting the correct port for your business, particularly when dealing with bulk emailing. Additionally, if you're seeking the easiest method to send bulk emails, consider trying Notifly. It's a versatile API platform that allows you to connect with your users worldwide seamlessly.
