Mailserver 25

The classic port 25!

Port 25 is the default port used for sending and receiving email messages over the Simple Mail Transfer Protocol (SMTP). It's a fundamental part of the email infrastructure, allowing email clients and servers to communicate with each other.

Here's a brief overview of what happens when you use port 25:

  1. SMTP connection: When you send an email, your email client (e.g., Outlook, Gmail, or Thunderbird) establishes a connection to the mail server (SMTP server) using port 25.
  2. Authentication: The mail server authenticates your email client using your email address and password (if required).
  3. Message submission: Your email client sends the email message to the mail server, which stores it temporarily.
  4. Message routing: The mail server routes the email message to the recipient's mail server using the recipient's email address.
  5. Delivery: The recipient's mail server receives the email message and stores it in the recipient's inbox.

However, it's worth noting that port 25 is often blocked by ISPs and email providers to prevent spamming and other malicious activities. This is because port 25 is a common entry point for spammers to send unsolicited emails.

To overcome this limitation, many email providers and ISPs offer alternative ports for sending and receiving email, such as:

When setting up your email client, you may need to specify the correct port number and authentication settings to ensure successful email transmission.