How can I set a VPN site to site (IPSec) between a Sophos XG330 fw and router with dinamic public IPs

Question

Hi everyone. 
 
 I was wondering How Can we set up a VPN site to site Between a Sophos XG firewall and a router which has Internet access through a modem which provides a dinamic public IPs 
 
 Thank you very much for help and assistance

LuCar Toni · Accepted Answer

You could configure the Router to initial the connection and XG as "Respond only". So basically XG will wait until the Router tries to reach the XG. Or you use on the router DDNS. 
 en.wikipedia.org/.../Dynamic_DNS