dns wildcard subdomains

Overview

Note the following section documents wildcard certificates and subdomains. You may want to use builtin facility within SimpleLogin to achieve the same results.

DNS configuration

If your DNS supports it, you can add a MX record to point *.mydomain.com to app.mydomain.com so that you can receive mails from any number of subdomains. To verify, the following command:

dig @1.1.1.1 *.mydomain.com mx

Should return:

*.mydomain.com. 3600  IN  MX    10 app.mydomain.com

SSL-Certificates are requested from Let`s Encrypt. Traefik is (by default) configured to use TLS-ALPN Challenge, because this works out-of-the-box without further configuration, as long as DNS resolves to your server.

One disadvantage of this configuration is that letsencrypt does not allow requesting wildcard certificates via TLS Challenge.

To request a wildcard certificate, edit .env file to set LE_CHALLENGE=dns, identify your DNS provider by setting LE_DNS_PROVIDER, and provide further details (i.e. credentials/API-Key, depending on your DNS provider) as ENV.

You can find all supported DNS providers and corresponding instructions here: https://go-acme.github.io/lego/dns/