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

NAME         top

       client.conf - client configuration file for cups

DESCRIPTION         top

       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/Preferences/org.cups.PrintingPrefs.plist file instead.  See
       the NOTES section below for more information.

       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

       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 hostname ("") 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.  The AllowDH option enables
            cipher suites using plain Diffie-Hellman key negotiation.  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.  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         top

       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         top

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

COPYRIGHT         top

       Copyright © 2007-2017 by Apple Inc.

COLOPHON         top

       This page is part of the CUPS (a standards-based, open source
       printing system) project.  Information about the project can be found
       at ⟨⟩.  If you have a bug report for this manual
       page, see ⟨⟩.  This page was obtained from the
       project's upstream Git repository ⟨⟩ on
       2017-09-15.  If you discover any rendering problems in this HTML ver‐
       sion of the page, or you believe there is a better or more up-to-date
       source for the page, or you have corrections or improvements to the
       information in this COLOPHON (which is not part of the original man‐
       ual page), send a mail to

26 June 2017                        CUPS                      client.conf(5)