location / {
proxy_pass http://IP_SERVER:81;
proxy_redirect http://IP_SERVER:81/ /;
proxy_set_header Host $host;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header X-Forwarded-Proto $scheme;
proxy_set_header X-Real-IP $remote_addr;
}
Так работает