Yep but even on small network we can use any of the ip of the A, B, C classes, again depending of our ISP or on some cases, like mine, we can use any of those reserved by ICANN.
Class A: up to 16.777.214 computers 0xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Network Computers
Class B: up to 65.534 computers 10xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Network Computers
Class C: up to 254 computers 110xxxxxxxxxxxxxxxxxxxxxxxxxxxxx Network Computers
ICANN reserved the following.
- Private IP class A : 10.0.0.1 to 10.255.255.254, very big networks.
- Private IP class B : 172.16.0.1 to 172.31.255.254, average size networks
- Private IP class C : 192.168.0.1 à 192.168.0.254, for small private networks.
ISPs use all of them here for their routers
NB: It is not to expalin to you, but it could be useful for newbies to know about how it works.