Как передавать данные на сервер без статического IP?

user www-data;
worker_processes auto;
pid /run/nginx.pid;
events {
        worker_connections 768;
        multi_accept on;
}
http {
        sendfile on;
        keepalive_timeout 15;
        proxy_buffers 8 64k;
        proxy_intercept_errors on;
        proxy_connect_timeout 1s;
        proxy_read_timeout 3s;
        proxy_send_timeout 3s;
        server {
            listen 80;
            server_name a.ru b.ru;
            access_log /var/log/nginx/1.access_log;
            error_log /var/log/nginx/1.error_log warn;
            charset utf-8;
            ssi on;
            ssi_value_length 1024;
            location / {
                proxy_pass http://10.8.0.6:9000;
                proxy_set_header X-Real-IP $remote_addr;
                proxy_intercept_errors off;
                proxy_read_timeout 5s;
                proxy_send_timeout 3s;
                gzip on;
                gzip_min_length 1024;
                gzip_proxied expired no-cache no-store private auth;
                gzip_types text/plain application/xml;
            }
        }
}