client.conf - client configuration file for cups (deprecated on macos)
The client.conf file configures the CUPS client and is normally located
in the /usr/local/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 "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 /usr/local/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. 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".
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
/usr/local/etc/cups/ssl/site.crl file, if present, provides a list of
revoked X.509 certificates and is used when validating certificates.
cups(1), default(1), CUPS Online Help (http://localhost:631/help)
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