| You are both slightly wrong, and slightly misunderstanding what I'm saying. > TLS is not mandatory in all cases, but if you want to use it, it is not an issue having a certificate. TLS is mandatory if you want to ensure your connection isn't being eavesdropped on or tampered with. > And even then you do not have to open any ports, even to letsencrypt verification, since you can use DNS verification method instead (for example using Cloudflare API). Yes this is called the ACME DNS challenge. I've used it many times, but if you want to be able to type in your server's domain name on a friend's TV and have it resolve to your server's IP address, then you'll need a public DNS record. > Certificate itself has nothing to do with DNS beyond the verification step. Yes it does, because most certificate authorities only sign certificates for fully qualified domain names, not IP addresses [1], so it obviously does involve the domain name system (you can view the domain name associated with a certificate in your browser, it'll be listed under the field "common name"). On a desktop computer you could get around this by editing the hosts file to map any domain name to any arbitrary IP address, but you can't do that on a TV. > And there can be a public DNS record but it doesn't say anything about ports. And the CT transparency log doesn't say anything about ports or IP addresses. I never said anything about ports, I said a public DNS record exposes the server's IP address. The whole point of the domain name system is to convert domain names into IP addresses, so that you can actually use the internet protocol to connect to a server's IP (internet protocol) address. Try running dig from the command line on literally any domain name and watch it expose the server's IP. Malicious bots can watch the transparency log to find out about new certificates [2], then run dig or some other tool to issue a DNS request (to determine the IP address of the server), and then start hammering the server to search for vulnerabilities or even potentially to just DDOS it. If you use a wildcard certificate it's harder for attackers to figure out which subdomain to query to find your server's IP, but with WireGuard I don't need a domain name at all. [1] https://community.letsencrypt.org/t/ssl-on-a-ip-instead-of-d... [2] https://community.letsencrypt.org/t/suspicious-web-traffic-a... |