To have your private network talk to each other and also for the home gateway setup to work, you need to assign IP addresses to all your system. Though you may assign any IP address to your private systems, you are not advised to do so. You are expected to use a specific set of IP addresses which have been reserved by IANA for private networks.
Table 1. Private IP Address assignments from RFC1918
IP Address Class | IP Address From | IP Address To | CIDR Notation | Subnet Mask |
---|---|---|---|---|
Class A | 10.0.0.0 | 10.255.255.255 | 10.0.0.0/8 | 255.0.0.0 |
Class B | 172.16.0.0 | 172.31.255.255 | 172.16.0.0/16 | 255.255.0.0 |
Class C | 192.168.0.0 | 192.168.255.255 | 192.168.0.0/24 | 255.255.255.0 |