I found options like .local and now .internal way too long for my private stuff. So I managed to get a two-letter domain from some obscure TLD and with Cloudflare as DNS I can use Caddy to get Let’s Encrypt certs for hosts that resolve to 10.0.0.0/8 IPs. Caddy has plugins for other DNS providers, if you don’t want to go with Cloudflare.
I found options like .local and now .internal way too long for my private stuff. So I managed to get a two-letter domain from some obscure TLD and with Cloudflare as DNS I can use Caddy to get Let’s Encrypt certs for hosts that resolve to 10.0.0.0/8 IPs. Caddy has plugins for other DNS providers, if you don’t want to go with Cloudflare.