Split Home Network

Note: Tested using KVM network only

Let's say, you want to have a network which is different than the one ISP setup for you.

Why

• You may want to have a guest network, which outside your home network for guests.
• You may want to have a network with full functional network devices, firewall, DNS server, DHCP server, etc.
• You may want to monitor the network inbound and outbound traffic.
• You may want to setup PXE, iPXE, BOOTP environment, configure DHCP options such as TFTP server, etc.
• You may want the VMs running on KVM routable network provide services to all machines, including Internet.
• You may want to have more IPs, want to have IP segments.
• You may want to have a more secure environment. In fact, if your router was setup by ISP, then they got full control of it, not you.

So, can you setup your own router to replace ISP route? Yes, you can, but you need to know whether you are allowed to do so by ISP. For my case, they asked me sign new agreement to say, service level drop and no technique support provided.

Before split

• You have a network which connect to ISP via the ISP route, which have DHCP and DNS service.

Requirement

• The ISP route can add route.
• One device or router with two network interfaces, and they are or can be on separate LAN.

Simple solution

If you have another router, let's say RouterA

• Connect WAN port of RouterA to ISP route LAN port
• Configure ISP LAN IP on RouterA's WAN port, such as 192.168.1.100,
• Make sure RouterA is in router mode, with it's own LAN, such as 192.168.100.0/24
• Add a route in ISP Route, network 192.168.100.0/24 gateway 192.168.1.10.

Done.

Difficult solution

Replace RouterA with your own home build router in the simple solution.