location / {
    proxy_pass http://backend;
}

location ~ ^/(smokeping|pgadmin4) {
    allow 192.168.11.0/25;
    deny all;
    
    proxy_pass http://backend;
}

/^(?!.*?([a-f])\1(?:\1|\d))[a-f](?:[a-f]|[3-9]\d*|[12]\d+)*$/