POP3, IMAP, and SMTP: Email Differences and Ports
Updated 2 months ago
This tutorial will explain the most widely used email protocols on the Internet: POP3, IMAP, and SMTP. Each has specific functions and ways of working. Read on to learn which configuration is best for your specific needs.
What is POP3 and what are its default ports?
Post Office Protocol version 3 (POP3) is a standard email protocol used to receive email from a remote server to a local email client.
POP3, together with client software such as Outlook or Thunderbird, lets you download emails to your local computer and then read them when you don’t have an internet connection. Note: when you use POP3 to connect to your mailbox, messages are downloaded locally and removed from the online server. This means that if you access your account from multiple locations, it may not be the best option for your needs.
Using POP3 is useful for storing your emails on your computer, which will reduce the space your email account uses on the web server (remember that emails tend to take up a lot of space on the server over time, reducing the useful megabytes available in your hosting plan).
By default, the POP3 protocol uses two ports:
Port 110 - the default unencrypted port
Port 995 - the port you need to use if you want to connect using secure (encrypted) POP3.
What is IMAP and what are its default ports?
The Internet Message Access Protocol (IMAP) is an email protocol used to access your emails on a remote server from a local client. IMAP and POP3 are the two most commonly used protocols for receiving emails. Both are supported by all modern email clients and web servers.
While POP3 assumes that you will access your email from only one application (e.g., Outlook), IMAP lets you access it simultaneously from multiple clients. This is why using IMAP is more convenient when you need to access an account from different devices, or when certain mailboxes are managed by multiple users.
By default, the IMAP protocol uses two ports:
Port 143 - the default unencrypted IMAP port.
Port 993 - the port you need to use if you want to connect using secure (encrypted) IMAP.
What is SMTP and what are its default ports?
Simple Mail Transfer Protocol (SMTP) is the standard protocol for sending emails over the Internet.
By default, it uses three ports:
Port 25 - the default unencrypted port
Port 9025 - this port is open on all servers in case port 25 is filtered (by your ISP, for example) and you want to send unencrypted emails using SMTP.
Port 465 - this is the port used if you want to send emails using secure (encrypted) SMTP.