In this section, we will give a brief overview of the most common protocols used in outgoing and incoming email interactions. The most common incoming email protocols are POP and IMAP. Most mail clients support all of these protocols. This article is to help users understand and choose which protocol should be selected for each user’s situation.
SMTP (Simple Mail Transfer Protocol):
SMTP is an email protocol used for sending email messages from one email account to another via the internet. Email protocols are sets of rules that let different email clients and accounts easily exchange information, and SMTP is one of the most common ones alongside POP and IMAP. It is also the only dedicated protocol for sending emails. SMTP is most commonly used on ports 25, 465 & 587.
POP (Post Office Protocol):
POP is an email protocol used to download emails from a mail server. Mail Clients such as Outlook using POP will download all emails from the server to the user’s computer, and then delete them on the server. Generally, POP uses port 110 to listen to the POP requests or securely using SSL (Secure Socket Layer) POP uses port number 995. The POP protocol assumes that only one client/computer will connect to the mailbox. Even though there is an option in most mail applications to leave copies of the emails on the server, it is not generally not used.
IMAP (Internet Message Access Protocol):
IMAP is another email protocol which is used to access emails from the server itself. Mail Clients such as Outlook using IMAP will synchronize a copy of the mail on the server to the user’s computer. IMAP listens on port 143 for incoming requests to synchronize emails or securely using SSL (Secure Socket Layer) IMAP uses port number 993. Basically, using IMAP protocol means that emails will be stored on the mail server and will be accessible from any Mail Clients anywhere if they all use IMAP.
SSL (Secure Socket Layer):
SSL creates a secure, encrypted connection between your email application and the email server. If SSL is enabled, all email connections between your computer and the mail server will be encrypted when you read, download/receive, and send email. This is the same technology you find when using online stores or banking websites which show that you are connecting securely.
TLS (Transport Layer Security):
TLS is a protocol that encrypts and delivers email data securely, for both inbound and outbound email traffic. It helps prevent eavesdropping between email servers, keeping messages private while they're moving between mail servers. TLS is being adopted as the standard for email security.
If you get stuck or have any questions feel free to contact our technical support team. They will be happy to assist you.