A list of email-server relevant ports

For future reference ;)

SMTP

PortDescription
25SMTP relay; usually plain text, can be TLS enc.
2525Alternative to 25 with possible TLS enc.
465Implicit SSL, no longer accepted standard
587IANA reg. as secure SMTP, req. TLS conn.

POP3

PortDescription
110Default, no enc.
995Secure POP3 with TLS or SSL

IMAP

PortDescription
143Default, no enc.
993Secure IMAP with TLS or SSL