HTTP | HyperText Transfer Protocol, port 80 |
HTTPS | Hypertext Transfer Protocol Secure, port 443 |
FTP | File Transfer Protocol, port 21 |
FTPS | also known as FTP-SSL, and FTP Secure, port 21 |
SMTP | Simple Mail Transfer Protocol, port 25 |
SMTPS | Simple Mail Transfer Protocol Secure, port 25 |
POP3 | Post Office Protocol 3, port 110 |
POP3S | Post Office Protocol 3 Secure, port 110 |
With the FTPS and SMTPS protocols, the STARTTLS extension allows the use of SSL or TLS on the standard port. The STARTTLS extension on the PO3S protocol, also on the standard port, allows the use of SSL or TLS to be negotiated using the STLS command.