http and https redirect on nginx with port 80 closed - http

Question

I have a project and use nginx to reverse proxy the request on the respectively port without having the port open. I also use Lets encrypt for ssl certification and everything works fine.
What I wanted to do was, to close port 80 and leave 443 open. I thought that ,
one more port close = a bit more security.
BUT, now the http to https redirect doesn't work (obviously I guess). Now the link only works if I type the prefix "https://" in front.
So I have two questions,
1) Is there a way to redirect the link to https without opening port 80?
2) How safe can we assume it is to leave port 80 open in order to make the redirection work, if the only app running is this one and only ports 443 and 22 are open?
my configuration file goes like this:
server {
listen 80;
server_name domain.com;
return 301 https://$server_name$request_uri;
}
server {
listen 443 ssl;
server_name domain.com;
add_header Strict-Transport-Security "max-age=31536000";
ssl_certificate /etc/letsencrypt/live/domain.com/fullchain.pem;
ssl_certificate_key /etc/letsencrypt/live/domain.com/privkey.pem;
include /etc/letsencrypt/options-ssl-nginx.conf;
ssl_dhparam /etc/letsencrypt/ssl-dhparams.pem;
if ($scheme != "https") {
return 301 https://$host$request_uri;
}
location / {
proxy_pass http://127.0.0.1:PORT;
proxy_http_version 1.1;
proxy_set_header Upgrade $http_upgrade;
proxy_set_header Connection 'upgrade';
proxy_set_header Host $host;
proxy_cache_bypass $http_upgrade;
}
}

Answer 1

No you can't forward trafffic from one port when it's closed on your server itself.
If possible and you have advanced network management you might be able to redirect traffic from 80 to 443 before it reaches your server.
For instance in Digital Ocean you have the ability under networks to add a loadbalancer and setup a redirect from port 80 to 443. That way you can leave port 80 closed on your server.