If you are in IT consulting field many times you will be assigned task of creating IPv4 addressing for enterprise. Here we will pass on to you our experience of designing internal IP addressing using private IP range.
On internal network we will use private IP range which is defined in RFC 1918.
Private IP Addresses characteristic
- Delay the transition to IPv6
- Require NAT translation
- Can not be routed to the Internet
- Number of networks must be reserved in each Address Class
- Dedicated for use on the Internal networks
IP Addresses reserved for use on private networks
|Address Class||Reserved Address Space|
|Class A||10.0.0.0 to 10.255.255.255|
|Class B||172.16.0.0 to 172.31.255.255|
|Class C||192.168.0.0 to 192.168.255.255|
Choosing internal IP range
When we are taking on a task of designing internal IP range in most cases we would suggest using Class A for any size internal network. The reason for this is simple. Class A gives us the most flexibility and room for expansion and growth. In some cases when you setting up very small office and you know there will be no more then few devices then class C should be fine.
We are designing Internal network with 10 internal departments separated by internal Vlans. We will in this case use class A with /24 mask
10.10.1.0/24, 10.10.2.0/24, 10.10.3.0/24 ……
This will give us 256 hosts per network and plenty of room for growth.