In the past I have setup public IPs on a network as follows:
The DSL ISP will give us a public subnet (/29). To use these IPs, this is how I configured the network:
- The modem/router has NAT switched off
- One IP from the subnet is assigned to the WAN side of the DSL modem/router (This is done automatically via PPPoA)
- One IP from the subnet is assigned to the LAN side of the DSL modem/router (I configure this myself, and usually just pick the next one after the WAN IP)
- The rest are used for the hosts on the LAN
The above works, and it's what I've always done. However there is one thing that is bugging me: How can the WAN and LAN sides of the modem/router have IPs in the same subnet? In the way of traditional routing, each interface is on a different subnet.
I'm very confused about this