The /etc/cups/client.conf and ~/.cups/client.conf files contain up to two directives that determine how the client behaves. Each directive is listed on a line by itself followed by its value. Comments are introduced using the number sign ("#") character at the beginning of a line.
Encryption Never Encryption IfRequested Encryption Required Encryption Always
The Encryption directive specifies the default
encryption settings for the client.
The default setting is IfRequested.
ServerName foo.bar.com ServerName 11.22.33.44 ServerName foo.bar.com:8631
The ServerName directive specifies sets the remote server that is to be used for all client operations. That is, it redirects all client requests to the remote server.
The default port number is 631 but can be overridden by adding a colon followed by the desired port number to the value.
The default is to use the local server ("localhost") or domain socket, if so configured.
SSLOptions None SSLOptions AllowSSL3 SSLOptions AllowRC4
Sets encryption options (only in /etc/cups/client.conf). By default, CUPS only supports encryption using TLS v1.0 or higher using known secure cipher suites. The AllowRC4 option enables the 128-bit RC4 cipher suites, which are required for some older clients that do not implement newer ones. The AllowSSL3 option enables SSL v3.0, which is required for some older clients that do not support TLS v1.0.