New DNS provider module

Plugins
8 
realdomain.com {
	tls {
		dns cloudflare {env.CLOUDFLARE_TOKEN}
		dns_challenge_override_domain cloudflaredomain.com
	}
}

And you need to make sure you set up the CNAME from your _acme-challenge.realdomain.com to cloudflaredomain.com.

Btw, challenge delegation is mentioned in Challenge Types - Let's Encrypt

It’s relatively new, it was merged in March.

But yeah you’re right it could be documented better. I think the best place would be in the How to use DNS provider modules in Caddy 2 wiki I think, which is open for anyone to edit, if you’d like to write it out once you’ve played around with this :+1: