Manage single wildcart domain for multiple sub domains

In certain situation it can be usefull to manage a single wildcart domain certificate for multiple subdomains.

Systems that need to aquire certificates for many domains and would otherwise hit ACME certificate limits could be configured this way.

If rate limits are not a concern it is better to use a configuration entry per sub domain.

Caddyfile example:

*.example.com, example.com {

    @sub1 host sub1.example.com
    handle @sub1 {
	# directives for sub1.example.com...
    }

    @sub2 host sub2.example.com
    handle @sub2 {
	# directives for sub2.example.com...
    }

	# directives for any other host...
}

Caddy will fetch a wildcart certificate for *.example.com and a regular cert for example.com and handle both in the same server block. You can use the host matcher to implement per-host handling if you need to, without it fetching a cert for that specific host.

This topic was heavily discussed in this issue¹