# Rule for legitimate ACME Challenge requests (like /.well-known/acme-challenge/xxxxxxxxx)
# We use ^~ here, so that we don't check other regexes (for speed-up). We actually MUST cancel
# other regex checks, because in our other config files have regex rule that denies access to files with dotted names.
location ^~ /.well-known/acme-challenge/ {
    auth_basic off;

    # Set correct content type. According to this:
    # https://community.letsencrypt.org/t/using-the-webroot-domain-verification-method/1445/29
    # Current specification requires "text/plain" or no content header at all.
    # It seems that "text/plain" is a safe option.
    default_type "text/plain";

    # This directory must be the same as in /etc/letsencrypt/cli.ini
    # as "webroot-path" parameter. Also don't forget to set "authenticator" parameter
    # there to "webroot".
    # Do NOT use alias, use root! Target directory is located here:
    # /var/www/common/letsencrypt/.well-known/acme-challenge/
    root /data/letsencrypt-acme-challenge;
}

# Hide /acme-challenge subdirectory and return 404 on all requests.
# It is somewhat more secure than letting Nginx return 403.
# Ending slash is important!
location = /.well-known/acme-challenge/ {
    return 404;
}