Options

This section describes advanced options that can be used to configure lego.

LEGO_CA_CERTIFICATES

The environment variable LEGO_CA_CERTIFICATES allows to specify the path to PEM-encoded CA certificates that can be used to authenticate an ACME server with an HTTPS certificate not issued by a CA in the system-wide trusted root list.

Multiple file paths can be added by using : (unix) or ; (Windows) as a separator.

Example:

# On Unix system
LEGO_CA_CERTIFICATES=/foo/cert1.pem:/foo/cert2.pem

LEGO_CA_SYSTEM_CERT_POOL

The environment variable LEGO_CA_SYSTEM_CERT_POOL can be used to define if the certificates pool must use a copy of the system cert pool.

Example:

LEGO_CA_SYSTEM_CERT_POOL=true

LEGO_CA_SERVER_NAME

The environment variable LEGO_CA_SERVER_NAME allows to specify the CA server name used to authenticate an ACME server with an HTTPS certificate not issued by a CA in the system-wide trusted root list.

Example:

LEGO_CA_SERVER_NAME=foo

LEGO_DISABLE_CNAME_SUPPORT

By default, lego follows CNAME, the environment variable LEGO_DISABLE_CNAME_SUPPORT allows to disable this support.

Example:

LEGO_DISABLE_CNAME_SUPPORT=true

There is a Let’s Encrypt blog post about the behavior of CNAMEs.

LEGO_DEBUG_CLIENT_VERBOSE_ERROR

The environment variable LEGO_DEBUG_CLIENT_VERBOSE_ERROR allows to enrich error messages from some of the DNS clients.

Example:

LEGO_DEBUG_CLIENT_VERBOSE_ERROR=true

LEGO_DEBUG_DNS_API_HTTP_CLIENT

⚠️ WARNING: This will expose credentials in the log output! ⚠️

Do not run this in production environments, or if you can’t be sure that logs aren’t accessed by third parties or tools (like log collectors).

You have been warned. Here be dragons.

The environment variable LEGO_DEBUG_DNS_API_HTTP_CLIENT allows debugging the DNS API interaction. It will dump the full request and response to the log output.

Some DNS providers don’t support this option.

Example:

LEGO_DEBUG_DNS_API_HTTP_CLIENT=true

LEGO_DEBUG_ACME_HTTP_CLIENT

The environment variable LEGO_DEBUG_ACME_HTTP_CLIENT allows debug the calls to the ACME server.

Example:

LEGO_DEBUG_ACME_HTTP_CLIENT=true