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 set‐
tings in the /Library/Preferences/org.cups.PrintingPrefs.plist file instead. See the NOTES section below for more informa‐
tion.

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 de‐
fault 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 sup‐
ported 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 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 sup‐
ported 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 sup‐
port 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 set‐
tings 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 cer‐
tificates and is used when validating certificates.

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

2021-02-28 CUPS client.conf(5)