client.conf

client.conf(5) OpenPrinting client.conf(5)

NAME

   client.conf - client configuration file for cups (deprecated on macos)

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/Preferences/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".

   DigestOptions DenyMD5

   DigestOptions None
        Specifies HTTP Digest authentication options.  DenyMD5 disables support for the original MD5 hash algorithm.

   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 ("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] [MaxTLS1.0] [MaxTLS1.1] [MaxTLS1.2] [MaxTLS1.3] [MinTLS1.0] [MinTLS1.1] [MinTLS1.2] [MinTLS1.3]

   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 re‐
        duced 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.  The MinTLS options set the minimum TLS version to support.  The MaxTLS options set the maximum TLS version to support.  Not
        all operating systems support TLS 1.3 at this time.

   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.

   UserAgentTokens None

   UserAgentTokens ProductOnly

   UserAgentTokens Major

   UserAgentTokens Minor

   UserAgentTokens Minimal

   UserAgentTokens OS

   UserAgentTokens Full
        Specifies  what  information  is  included  in  the  User-Agent  header  of HTTP requests.  "None" disables the User-Agent header.  "ProductOnly" reports "CUPS".  "Major" reports
        "CUPS/major IPP/2".  "Minor" reports "CUPS/major.minor IPP/2.1".  "Minimal" reports "CUPS/major.minor.patch IPP/2.1".   "OS"  reports  "CUPS/major.minor.path  (osname  osversion)
        IPP/2.1".  "Full" reports "CUPS/major.minor.path (osname osversion; architecture) IPP/2.1".  The default is "Minimal".

   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.