Protocols
---------
Note that all these protocols can be layered atop TLS
POP3 - port 110 ; STARTTLS can be on this port, or on 995 (POP3S)
IMAP - port 143
IMAPS (IMAP over SSL) - port 993
SMTP - port 25; client SW typically use 587 (plaintext) or 465 (TLS)
  ESMTP servers can use TLS; avoid MITM attacks by DANE (part of DNSSEC)
  SMTP-Strict Transport Security (relies on CAs).

OS X 10.4/5 Email Clients
OS X Mail.app - TLS 1.0/1.1
TenFourBird (Thunderbird 38) - email & USENET newsgroups; about:config is in
  General section of Advanced tab ("Config Editor")
Mailsmith - POP3 only
Seamonkey - email & USENET newsgroups

Provider Settings
-----------------
Gmail : imap.gmail.com, port 993, TLS/SSL
       SMTP: smtp.gmail.com, port 465 or 587, TLS/SSL
  crim...,envKan  ; bergs...,

Yahoo: imap.mail.yahoo.com, port 993, TLS
       SMTP: smtp.mail.yahoo.com, port 465 or 587, TLS/SSL yes
       envKan...

CenturyLink/Embarq: username is full email address
  IMAP: mail.centurylink.net, port 993, TLS/SSL
  POP: pop.centurylink.net, port 995, SSL/TLS
  SMTP: smtp.centurylink.net, port 587, STARTTLS
  crim..., envGash2

Mailfence: imap.mailfence.com, port 993, TLS/SSL
  smtp.mailfence.com, port 465, TLS/SSL

Newton.org: normal IMAP & SMTP ports
  crim...VGX, varFal...

Outlook.com/Office 365 mail: IMAP server = outlook.office365.com, port 993, TLS
  POP3S: outlook.office365.com, port 995, encryption TLS
  SMTP: smtp.office365.com, port 587, STARTTLS, can req. TLS 1.2