One of the earliest ways to communicate over the Internet was through sending and receiving emails. Today, almost all people who use the Internet have at least one email id. An email protocol is a set of rules, which aids the client to send and receive the information from or to a mail server in a proper way.
The article covers the most common types of email protocols used on the Internet. These include SMTP, IMAP, and POP3. Each of these email protocols has a particular function, as well as, way of functioning.
So, here are the email protocols, which you should be acquainted with as an admin:
POP3 Email protocol
Most Internet users who have email ids typically use some kind of “client’ software such as the Outlook to manage and access their email at some time of the others. Such email clients can need the configuration of POP3 or Post Office Protocol to retrieve emails before these messages can be received from the server.
Which email protocol allows an email client to download email messages to the local computer?
Pop3 is an email protocol that enables the email client to download emails from a remotely located server to your local computer.
You can read the email messages even when you are not online. If a protocol enables a user to access their account from several locations, it might not be the most appropriate choice for them. However, when one uses the POP3 protocol, the emails are saved on the local computer. It also diminishes the space used by an email account on the server.
There should be a TCP/IP connection for the client to get the emails from a remote server. Ever since its 1st version came out in 1984, the POP3 protocol has emerged as one of the most widely-used email protocols. Today, it is used by almost every email client. The email protocol is immensely popular because of its simple configuration, maintenance, and operation.
Its popularity lies in the protocol’s simplicity to configure, operate, and maintain. Internet Service Provides host email servers use this email protocol also to hold and receive emails meant for their subscribers. Such subscribers usually use email client software for checking their mailbox located on a remote mail server. They are also used to download all such emails meant for them from time to time.
After an email client has successfully downloaded or retrieved the emails, they get removed from the mail server. However, there are certain email clients, which enable their clients whether they want their emails to be saved or copied on the mail server for a certain period of not.
Post Office Protocol Version 3 can work on two different ports by default. These are as follows:
- Port 995– It is the port the user may require using when they wish a secure connection via POP3.
- Port 110– It is considered to be the default non-encrypted port for POP3.
Applications that use POP3
As this email uses the basic technique for receiving and storing emails, it enjoys compatibility with any kind of email program, which has been configured for hosting a protocol. Widely-used email protocols such as Outlook Express offer native support for POP3 email protocol.
Apart from email client programs that use this email protocol for retrieving emails, a synchronization and backup program called SyncBackPro also uses the POP3 email protocol.
How does the POP3 email protocol function?
Every time a user checks whether there is a new email or not, the email client software establishes a connection with the POP3 server. The email client has to then provide authentication details such as a username, as well as, password to this mail server to authenticate.
After a connection is established, the client program has to give a set of text-based commands so that all email messages can be retrieved. The client software then stores the downloaded email messages on the local system of the user as new emails. It deletes the email copies on the server and then disconnects from this email server.
The email copies on the server are deleted by default after they are retrieved by the email clients. As such, the emails are linked to a particular computer and it is not possible to get the same emails from the email client installed in another machine. The problem can be resolved when the user configures their email client settings in a manner that maintains the emails’ copy on the mail server.
By default, the POP releases the space of the mailbox on a server. The attachments and emails are deleted at this server after downloading them on a particular computer. It happens every time an email client software checks for the existence of new emails. Offline email messages which are stored in a computer of the user do not suffer from the limitation of mailbox size. The only limitation is the capacity of the hard drive storage on a personal computer.
Merits of POP3
- It is extremely popular and easy to use and configure
- Email storage capacity is only restricted by the hard disk storage
- Less storage space is required on the server as all emails are saved on a local computer
- It is easy and fast to open attachments because they have been already downloaded
- Emails are saved to the local machine of the user. Messages can be read even when the user is not online
Demerits of POP3
- A user cannot access emails from some machine unless the machine has been configured for doing so.
- There could be viruses in the email attachment exposing the personal computer of the user to harm whenever they are opened. The virus scanner may not be able to detect the presence of such viruses.
- It is not unusual for the email folders to get corrupted thus losing the complete mailbox at one go.
- It may be difficult to export the user’s local email folder to another physical machine or email client software.
The IMAP or Internet Message Access Protocol is an email protocol, which is used to access emails from the local client on a remote server. POP3 and IMAP are the two most popular email protocols on the Internet to retrieve emails. All modern web servers, as well as, email clients’ support both these protocols.
On one hand, the POP3 email protocol assumes that the email has to be accessed just from one application, the Internet Message Access Protocol enables parallel access by many clients. It for this particular reason the IMAP protocol is more appropriate for a user if he/she has to access their emails from multiple locations or when multiple users manage those messages.
The protocol was initially proposed in 1986 and has five different versions, which are as follows:
It was first proposed in 1986. There exist five versions of IMAP as follows:
- Original IMAP
The IMAP protocol operates on two different ports by default
Port 993: It is the port the user has to use if they want a secure connection using IMAP
Port 143: It is the default non-encrypted port of IMAP
SMTP email protocol
SMTP or Simple Mail Transfer Protocol is the standard mail protocol to send emails over the Internet. The SMTP protocol operates on three different ports by default, which is as follows:
- Port 465: It is the port a user should use if they want to transmit email messages securely using SMTP.
- Port 2525: The port is used on all the SiteGround web servers if port 25 is filtered.
- Port 25 It is the default non-encrypted port of the SMTP email protocol.
Which of the following protocols can be enabled so email is encrypted on a mobile device?
The two major kinds of protocols for email encryption are PGP/MIME and S/MIME. S/MIME or Secure/Multipurpose Internet Mail Extensions comes in-built into most iOS and OSX devices. The protocol depends on a centralized authority for picking the encryption logarithm. It is immensely popular as it comes in-built into huge web-based email organizations such as Outlook and Apple.
On the other hand, Pretty Good Privacy/Multipurpose Internet Mail Extensions or PGP/MIME depends on a decentralized trust system. The protocol was developed for addressing and resolving security-related issues being faced for plain text messages.
How to encrypt your email messages on an iOS device?
By default, iOS devices come with in-built support for S/MIME. Here are the steps to encrypt emails on an iOS device:
- Navigate to Advanced Settings of your device. Switch on S/MIME
- “Encrypt by Default” should be changed to “yes”
- If an email message is composed, a lock icon appears next to the mail recipient. The lock icon has to be clicked so that is it closed and the email is encrypted.
How to encrypt your email messages on an Android device?
Emails received on an Android device can be encrypted using PGP/MIME, as well as, S/MIME. However, both these protocols required a 3rd-party app and additional setup.