client.conf(5)							    Apple Inc.							    client.conf(5)

NAME

       client.conf - client configuration file for cups

DESCRIPTION

       The client.conf file configures the CUPS client and is normally located in the /etc/cups and/or ~/.cups directories.  Each line in the file
       can be a configuration directive, a blank line, or a comment. Comment lines start with the # character.

       Note: Starting with macOS 10.7, this file is only used by command-line and X11 applications plus the IPP backend.  The ServerName directive
       is  not	supported  on  macOS  at  all.	 Starting  with  macOS	10.12,	all applications can access these settings in the /Library/Prefer-
       ences/org.cups.PrintingPrefs.plist file instead.  See the NOTES section below for more information.

   DIRECTIVES
       The following directives are understood by the client. Consult the online help for detailed descriptions:

       AllowAnyRoot Yes

       AllowAnyRoot No
	    Specifies whether to allow TLS with certificates that have not been signed by a trusted Certificate Authority.  The default is "Yes".

       AllowExpiredCerts Yes

       AllowExpiredCerts No
	    Specifies whether to allow TLS with expired certificates.  The default is "No".

       Encryption IfRequested

       Encryption Never

       Encryption Required
	    Specifies the level of encryption that should be used.

       GSSServiceName name
	    Specifies the Kerberos service name that is used for authentication, typically "host", "http", or "ipp".  CUPS adds the  remote  host-
	    name ("name@server.example.com") for you. The default name is "http".

       ServerName hostname-or-ip-address[:port]

       ServerName /domain/socket
	    Specifies  the  address  and optionally the port to use when connecting to the server.  Note: This directive is not supported on macOS
	    10.7 or later.

       ServerName hostname-or-ip-address[:port]/version=1.1
	    Specifies the address and optionally the port to use when connecting to a server running CUPS 1.3.12 and earlier.

       SSLOptions [AllowDH] [AllowRC4] [AllowSSL3] [DenyCBC] [DenyTLS1.0]

       SSLOptions None
	    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.  Security is reduced when Allow options are used.  Security is enhanced when Deny options are used.  The
	    AllowDH option enables cipher suites using plain Diffie-Hellman key negotiation  (not  supported  on  systems  using  GNU  TLS).   The
	    AllowRC4  option  enables  the 128-bit RC4 cipher suites, which are required for some older clients.  The AllowSSL3 option enables SSL
	    v3.0, which is required for some older clients that do not support TLS v1.0.  The DenyCBC option disables all CBC cipher suites.   The
	    DenyTLS1.0 option disables TLS v1.0 support - this sets the minimum protocol version to TLS v1.1.

       TrustOnFirstUse Yes

       TrustOnFirstUse No
	    Specifies whether to trust new TLS certificates by default.  The default is "Yes".

       User name
	    Specifies the default user name to use for requests.

       ValidateCerts Yes

       ValidateCerts No
	    Specifies whether to only allow TLS with certificates whose common name matches the hostname.  The default is "No".

NOTES

       The  client.conf  file  is  deprecated  on  macOS  and will no longer be supported in a future version of CUPS.	Configuration settings can
       instead be viewed or changed using the defaults(1) command:
       defaults write /Library/Preferences/org.cups.PrintingPrefs.plist Encryption Required
       defaults write /Library/Preferences/org.cups.PrintingPrefs.plist TrustOnFirstUse -bool NO

       defaults read /Library/Preferences/org.cups.PrintingPrefs.plist Encryption
       On Linux and other systems using GNU TLS, the /etc/cups/ssl/site.crl file, if present, provides a list of revoked X.509 certificates and is
       used when validating certificates.

SEE ALSO

       cups(1), default(1), CUPS Online Help (http://localhost:631/help)

COPYRIGHT

       Copyright (C) 2007-2017 by Apple Inc.

19 October 2017 						       CUPS							    client.conf(5)