POP3
POP3 is a protocol to retrieve email.
POP3 stands for Post Office Protocol 3.
POP3 has been around for a long time. It’s used to retrieve email messages from the Internet server provider. It then downloads the mail to the local mail client. You can then have the option to delete the mail from the server once it’s been downloaded. This process of deleting the email from the server only made sense if you only had 1 device that was downloading the mail. Nowadays we can have multiple devices collecting email, so deleting the email from the server once it’s downloaded to one device doesn’t make sense.
Legacy equipment may still use POP3. To configure POP3 you’ll need the name of the POP3 server (hostname) and a username and password.
POP3 Ports
The mail configuration set up may ask your for the network ports. By default, POP3 uses TCP Port 110. If you’re using POP3 over a secure channel, also known as POP3S, the default port is TCP Port 995
IMAP
IMAP is another protocol to retrieve email.
IMAP stands for Internet Message Access Protocol. Today we use version 4 so it’s IMAP4.
Mail is accessed and stored on a central server. IMAP supports folders and server side searches.
To configure mail using IMAP, you’ll need the name of the IMAP server (host name), and a username, and password.
IMAP Ports
By default IMAP uses TCP Port 143. IMAP with SSL, called IMAPS, uses TCP Port 993.
SMTP
SMTP is the protocol for sending mail from your local device to a mail server or between mail servers. Autentication is usually required to configure SMTP. The SMTP credentials may be different than the incoming mail.
SMTP Ports
SMTP uses TCP Port 25. SMTP with authentication uses TCP Port 587.
SSL
SSL stands for Secure Sockets Layer. SSL encrypts traffic between the mobile device and your email server. However, it does not provide end to end encryption. You can’t be sure the email will be encrypted when it is sent to other email servers.
Incoming SSL uses port 995 or 993. Outgoing SSL uses port 465.
Microsoft Exchange
If you’re using a corporate email you could be using Microsoft Exchange which has a different process for sending and receiving email.
Microsoft Exchange goes beyond just email. It also includes Contacts, Calendars, and Reminders. These items can also be synced across various mobile devices.
To configure Microsoft Exchange you’ll need the email addresses, server name, domain name, username, and password
Microsoft Exchange provides additional security for email messages themselves. You can encrypt your messages with S/MIME.
S/MIME
S/MIME stands for Secure/Multipurpose Internet Mail Extensions. S/MIME allows you to encrypt and digitally sign the message that you’re sending and receiving from Microsoft Exchange. With S/MIME you accomplish encryption, authentication via digital signatures, and message integrity. S/MIME provides end to end security.
However, S/MIME is incompatible with server side malware and spam scanning, because the scanners wont be able to access the content of the email.
S/MIME integration requires a certificate system or Public Key Infrastructure (PKI), such as Microsoft’s Active Directory Certificate Services.
Commercial email Providers
Commercial email providers such as iCloud, Google, Yahoo, etc. can also be configured on your mobile device. Your mobile device may be preconfigured with these email providers and all you have to do is click on the email provider and provide your username and password to perform a set up. Example email providers:
- Gmail: Supports IMAP4 and POP3
- Exchange Online (hosted email): Supports IMAP4 and POP3
- iCloud Mail: This is Apple’s mail provider. Only supports IMAP4.
- Yahoo Mail: Supports IMAP4 and POP3