The answer lies in the configuration of the routers. They must be able to route client requests from the client’s network to the DHCP server’s network. One of these simple rules of the router is " IP helper."This simply tells the router to redirect DHCP requests to the known IP address of the DHP server. I used to always use a VPN or proxy server, but this slowed down my connection and my computer. There are some VPNs that are worse than google chrome, it was mostly because I was spending time on Pirate Bay and it was blocked a lot. You can use one of PirateBay proxies to access it always with no problem.