Main PLUG discussion list Hi, As you may know I am working on a home PHP webserver. I have the LAMP stack operational along with BIND and Let's Encrypt. I need to understand and get Postfix and Dovecot functioning. Here is what I have pulled together. Please le me know if this is accurate, if I let anything out, or any other information I need to know. Thanks!! MUA : Mail User Agent – Your email client. (port 587) MTA : Mail Transfer Agent (port 25) (port 587 or 465 ?) MDA : Message Delivery Agent MSA : Mail Submission Agent SMTP : Simple Mail Transfer Protocol POP3 : Post Office Protocol IMAP : Internet Message Access Protocol SSL : Secure Socket Layer TLS : Transport Layer Security • User client (Mail User Agent) sends an email to the Mail Transfer Agent via port 25, 587, 465, or 2525. I’ve read that port 465 should no longer be used. • I read port 587 should only be used for submissions (i.e., mail client to mail server), port 25 should only be used for relaying (i.e., mail server to mail server communications). • Mail Transfer Agents transfer email to other Mail Transfer Agents via port 25 exclusively. • Mail Transfer Agent stores the email on the server. • The user client (Mail User Agent) interacts with the mail server via the Message Delivery Agent using POP3 or IMAP. This transaction can be secured by a Secured Socket Layer certificate referred to as TLS (Transport Layer Security), POP3S or IMAPS, or not secured POP3 or IMAP. • The POP3 and IMAP and ports: ◦ IMAP - 143 ◦ IMAPS - 993 ◦ POP3 - 110 ◦ POP3S – 995 Thanks!! --------------------------------------------------- PLUG-discuss mailing list - PLUG-discuss@lists.phxlinux.org To subscribe, unsubscribe, or to change your mail settings: https://lists.phxlinux.org/mailman/listinfo/plug-discuss