Can I use the same certificate for domains behind Cloudflare?

Question

Nginx

Consider the situation, I generated certificates from let's encrypt for a domain not for cloudflare

/etc/letsencrypt/chain.pem /etc/letsencrypt/fullchain.pem
/etc/letsencrypt/privkey.pem
I

added to the nginx config for a domain that is behind CloudFlare the path to certificates from let`s encrypt

ssl_certificate /etc/letsencrypt/fullchain.pem
ssl_certificate_key /etc/letsencrypt/privkey.pem
ssl_trusted_certificate /etc/letsencrypt/chain.pem; Enabled SSL FULL

mode in Cloudflare It seems to work, but how adequate and correct is it?

Answer 1

This is adequate, you can put the last Full (strict) to make it quite adequate

Answer 2

maybe, but why? testing technique? or critical data?