SSLOPT (JANUS DEFINE parameter)
Specifies optional use of SSL
SSLOPT is a parameter on JANUS DEFINE, which defines and sets characteristics of a Janus port. It is specified without a value.
Valid only for CLSOCK and FTPSERVER (as of Sirius Mods 8.0) SSL (Secure Sockets Layer) ports, this parameter specifies that the use of SSL-like encryption is optional for applications using the port. An SSL port is one that includes the SSL parameter in its definition.
CLSOCK ports
If SSLOPT is set for an SSL CLSOCK port, the SSL or NOSSL parameter (or their equivalents) on $Sock_Conn and the applicable Janus Sockets object method calls determines whether or not the connection will be encrypted. If the connection is encrypted, the SSLPROT setting influences the type of encryption protocol that will be used.
If SSLOPT is set for an SSL port, but no SSL or NOSSL parameter (or their equivalents) is specified on $Sock_Conn and the applicable Janus Sockets object method calls, the connection is not encrypted by default.
If SSLOPT is not set for an SSL port, SSL is used for all client connections from the port, and specifying the NOSSL parameter on a $Sock_Conn call is treated as an error.
FPTSERVER ports
If SSLOPT is set for an SSL FTPSERVER port, FTP clients can use the FTP Server without using the FTP AUTH command to switch to using SSL. If SSLOPT is not specified, a client attempt to logon without issuing an AUTH command to switch to SSL results in a rejection of the logon attempt (with an FTP 534 response) and a closing of the connection.
In other words, without the SSLOPT parameter, FTP commands and data must be exchanged over an encrypted SSL connection.
SSL support was made available for FTPSERVER ports in Sirius Mods 8.0.