The following chart provides settings to assist in the configuration of various email clients.

Protocol Server Port Encryption
SMTP Submission 587 Requires STARTTLS
IMAP4 143 Requires STARTTLS
IMAPS 993 Requires SSL/TLS


  • STARTTLS may be referred to as “auto” or “negotiated encryption”
  • POP3 is also available on port 110 (STARTTLS) or 995 (SSL/TLS) but it’s use is strongly discourage

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