Category Archives: POP3

Mail Server – TLS/SSL Ports

For IMAP, there are only two ports to choose from and only 3 total configurations:

Port 993: TLS checked – Direct TLS secure connection
Port 143: TLS checked – StartTLS is used to initiate a secure connection
Port 143: TLS unchecked – Connect insecurely

For POP, it’s the same situation:

Port 995: TLS checked – Direct TLS secure connection
Port 110: TLS checked – StartTLS is used to initiate a secure connection
Port 110: TLS unchecked – Connect insecurely

For SMTP, it’s a little bit more complicated:

Port 465: TLS checked – Direct TLS secure connection
Port 587: TLS checked – StartTLS is used to initiate a secure connection
Port 587: TLS unchecked – Connect insecurely.
Port 25: TLS checked – StartTLS is used to initiate a secure connection (never seen this work)
Port 25: TLS unchecked – Connect insecurely