服务器PC如何使用Asp.net访问客户端PC的SQL Server数据c＃

I have more than 100 clients on different networks (not on LAN) e.g. one is in USA and other in UK and other in Dubai and so on. My all clients PC using the same Windows application and their own local DB.and using internet with Router.as you know due to router public IP always change after 24 hour. I have more than 100 clients on different netwo