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How to Use POP3, SMTP and IMAP Protocols

Email protocols are systems that allow you to send or receive messages. Each one is different and comes with its own set of pros and cons. You will have to determine for yourself which system is ideal.

In this tutorial, I’m going to go over the basics of the three most popular protocols: POP3, SMTP and IMAP. With this basic understanding, you will be able to make a more informed decision when creating email accounts and what systems to use.

Using POP3 Email Protocols

The Post Office Protocol version 3, or POP3 for short, is one of the most common methods for receiving email. In this protocol, your messages are downloaded directly to a device and readable even if you’re not online. This is convenient in many settings, especially if you’re in an area where Internet is sporadic at best.

Because POP3 downloads messages, you don’t have to be constantly worried about servers becoming too full. If there is a quota on your hosting account for messages, this can fill up over time.

On the other hand, you can set software such as Outlook to leave a copy of the message on the server. This is helpful if you use more than one device throughout the day.

The common ports for POP3 are:

Port 110 – A standard port for email that comes from an unsecured server.
Port 995 – A secured port for email retrieval.

Using SMTP Email Protocols

Simple Mail Transfer Protocol, or SMTP, is essentially the standard method of sending email. It accompanies the use of POP3 whether the system is secured or not.

Unfortunately, some ISPs will SMTP their services by default if it’s using an unsecure port. This helps reduce the spread of spam and helps keep the Internet free of unsolicited messages. If your ISP is one of these, you may have to rely on Webmail if you want to send messages.

Luckily, these same ISPs often don’t block the unsecured POP3 connections. This means you can still get email when using apps like Outlook or Mozilla Thunderbird.

The common ports for SMTP are:

Port 25 – This messaging port is unsecured as is the one that is often blocked by some ISPs.
Port 465 – This port is the secured access point for SMTP.

Using Other Ports

Some systems can be set up to send and receive email using different ports. For instance, some hosts will allow port 2525 to be used to send messages in case the ISP is blocking port 25. If you need help in this instance, you may want to contact customer support.

Using IMAP Email Protocols

The Internet Message Access Protocol, or IMAP, is a system that is essentially web-based. Instead of downloading email as in POP3, you access a live view of the online server. This is convenient if you use a smartphone and computer systems to access email. Instead of downloading the message and removing it from the server, the IMAP keeps everything online.

The only real drawback to IMAP is the fact you need an Internet connection to use it. If you travel into a cellular dead zone, you won’t be able to access messages on your mobile device. The trade-off is the speed and flexibility in which IMAP functions.

The common ports for IMAP are:

Port 143 – For messaging that is not secured.
Port 993 – If you have secure encryption on your mail server.

Chose the Best Method or Your Needs

Email protocols are relatively simple system to master, once you have a grasp of how it all works. It all boils down to convenience and security. Not all methods are ideal for everyone, and you should take a moment to think which is the best for your situation.

Author: Josh Dargie

My name is Josh Dargie and I’m the Operations Manager at GreenGeeks. I’ve been with the company since 2009. I have over 16 years of experience working with and for various web hosting providers specifically in development, day-to-day operations and customer service.

Updated on July 17, 2017

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