acme-client.conf(5) - OpenBSD manual pages

NAME

acme-client.conf — acme-client configuration file

DESCRIPTION

The acme-client.conf config file is divided into three main sections:

Macros: User-defined variables may be defined and used later, simplifying the configuration file.
Authorities: TLS authorities that can be contacted via ACME.
Domains: Domains that the user wants to receive TLS certificates for.

Additional configuration files can be included with the include keyword, for example:

include "/etc/acme-client.sub.conf"

The current line can be extended over multiple lines using a backslash (‘\’). Comments can be put anywhere in the file using a hash mark (‘#’), and extend to the end of the current line. Care should be taken when commenting out multi-line text: the comment is effective until the end of the entire block.

Argument names not beginning with a letter, digit, underscore or '/' must be quoted.

MACROS

Macros can be defined that will later be expanded in context. Macro names must start with a letter, digit, or underscore, and may contain any of those characters. Macro names may not be reserved words. Macros are not expanded inside quotes.

For example:

le="letsencrypt"
domain example.com {
	sign with $le
}

AUTHORITIES

The configured certificate authorities.

Each authority section starts with a declaration of the name identifying a certificate authority.

authority name {...}: The name is a string used to reference this certificate authority.

It is followed by a block of options enclosed in curly brackets:

account key file: Specify a file used to identify the user of this CA.
agreement url url: Specify the url of a contract under which the certificates are supplied by the certificate authority.
api url url: Specify the url under which the ACME API is reachable.

An example authority block:

authority letsencrypt {
	agreement url https://letsencrypt.org/documents/LE-SA-v1.1.1-August-1-2016.pdf
	api url "https://acme-v01.api.letsencrypt.org/directory"
	account key "/etc/ssl/private/my-acme.key"
}

DOMAINS

The domains that are configured to obtain SSL certificates through ACME.

domain name {...}: Each domain section begins with the domain keyword followed by the domain name.

It is followed by a block of options enclosed in curly brackets:

alternative names {...}: Specify a list of alternative names the certificate will be valid for.
domain key file: The private key file for which the certificate will be obtained.
domain certificate file: The filename of the certificate that will be issued.
domain chain certificate file: The filename in which to store the certificate chain that will be returned by the CA. It needs to be in the same directory as the domain certificate (or in a subdirectory) and can be specified as a relative or absolute path.
domain full chain certificate file: The filename in which to store the full certificate chain that will be returned by the CA. It needs to be in the same directory as the domain certificate (or in a subdirectory) and can be specified as a relative or absolute path. This is a combination of the domain certificate and the domain chain certificate in one file, and is required by most browsers.
sign with authority: The certificate authority (as declared above in the AUTHORITIES section) to use for this domain is selected.
challengedir path: The directory in which the challenge file will be stored. If it is not specified, a default of /var/www/acme will be used.

An example domain declaration looks like this:

domain example.com {
	alternative names { secure.example.com www.example.com }
	domain key "/etc/ssl/private/example.com.key"
	domain certificate "/etc/ssl/example.com.crt"
	domain full chain certificate "/etc/ssl/example.com.fullchain.pem"
	sign with letsencrypt
	challengedir "/var/www/acme"
}

An httpd.conf(5) server declaration to use that certificate looks like this:

server "example.com" {
        alias "www.example.com"
        alias "secure.example.com"
        listen on $ext_addr port 80
        listen on $ext_addr tls port 443
        tls certificate "/etc/ssl/example.com.fullchain.pem"
        tls key "/etc/ssl/private/example.com.key"
        location "/.well-known/acme-challenge/*" {
                root "/acme"
                root strip 2
        }
        root "/htdocs"
}

FILES

/etc/acme-client.conf: acme-client(1) configuration file

HISTORY

The acme-client.conf file format first appeared in OpenBSD 6.1.

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