SMTP, POP3 and IMAP

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SMTP, POP3 and IMAP are TCP/IP protocols used for mail delivery. Email clients use POP3 and IMAP protocol to retrieve email from the server (incoming mail) over TCP/IP connection. Outgoing mail for both POP and IMAP clients uses the SMTP. Main difference between POP3 and IMAP is,

  • POP3 – Downloads email locally
  • IMAP – Mail is stored on the mail server

SMTP

Simple Mail Transfer Protocol (SMTP) servers handle the sending of your e mail messages to the Internet. The SMTP server handles outgoing e mail, and is used in conjunction with a POP3 or IMAP incoming e mail server.

POP3

Post Office Protocol 3 (POP3) servers hold incoming e mail messages until you check your e mail, at which point they’re transferred to your computer. POP3 is the most common account type for personal e mail. Messages are typically deleted from the server when you check your e mail.

IMAP

Internet Message Access Protocol (IMAP) servers let you work with e mail messages without downloading them to your computer first. You can preview, delete, and organize messages directly on the e mail server, and copies are stored on the server until you choose to delete them. IMAP is commonly used for business e mail accounts.

Default Ports

  • SMTP AUTH: Port 25 or 587 (some ISPs are blocking port 25)
  • SMTP StartTLS Port 587
  • SMTP SSL Port 465
  • POP Port 110
  • POP SSL Port 995
  • IMAP Port 143
  • IMAP SSL Port 993
  • IMAP StartTLS Port 143

The following list of SMTP, POP3, and IMAP server should help you if you don’t know what mail server you should use for your mail account.

  SMTP POP3 IMAP
Gmail smtp.gmail.com pop.gmail.com imap.gmail.com
  SSL Port 465 SSL Port 995 SSL Port 993
  StartTLS Port 587
TLS/SSL encryption required: yes
Please make sure, that POP3 access is enabled in the account settings. Login to your account and enable POP3. Please make sure, that IMAP access is enabled in the account settings. Login to your account and enable IMAP.
Outlook.com smtp.live.com pop3.live.com imap.mail.yahoo.com
  StartTLS Port 587 SSL Port 995 SSL Port 993
  TLS/SSL encryption required: yes TLS/SSL encryption required: yes  
Yahoo Mail smtp.mail.yahoo.com pop.mail.yahoo.com  
  SSL Port 465 SSL Port 995  
Yahoo Mail Plus plus.smtp.mail.yahoo.com plus.pop.mail.yahoo.com plus.imap.mail.yahoo.com
  SSL Port 465 SSL Port 995 SSL Port 993
Yahoo UK smtp.mail.yahoo.co.uk pop.mail.yahoo.co.uk imap.mail.yahoo.co.uk
  SSL Port 465 SSL Port 995 SSL Port 993
Yahoo Deutschland smtp.mail.yahoo.de pop.mail.yahoo.de imap.mail.yahoo.de
  SSL Port 465 SSL Port 995 SSL Port 993
Yahoo AU/NZ smtp.mail.yahoo.com.au pop.mail.yahoo.com.au imap.mail.yahoo.com.au
  SSL Port 465 SSL Port 995 SSL Port 993
Windows Live (Hotmail) smtp.live.com pop3.live.com  
  StartTLS Port 587 SSL Port 995