Network - Private Network
About
A private network has no Internet access whereas a public one has.
A private network is also known as private subnet
A private subnet connect a host to the Internet without exposing their private IP address by routing their traffic through:
- a Network Address Translation (NAT) gateway
- or a proxy gateway
that are located in a public subnet.
A private network is a network that uses RFC 1918 IP address space.
To allow organizations to freely assign private IP addresses, the NIC has reserved certain address blocks for private use.
It can host the backend systems such as databases or application servers
Scope
There is 2 private scope:
- Link-local addresses. They are designed to be used for addressing on a single link for purposes such as auto-address configuration, neighbor discovery, or when no routers are present.
- Site-local addresses. They are designed to be used for addressing inside of a site without the need for a global prefix.
Block
The following IP blocks are reserved for private IP addresses.
| Class | Starting IP Address | Ending IP Address |
|---|---|---|
| A | 10.0.0.0 | 10.255.255.255 |
| B | 172.16.0.0 | 172.31.255.255 |
| C | 192.168.0.0 | 192.168.255.255 |
In addition to above classful private addresses, 169.254.0.0 through 169.254.255.255 addresses are reserved for Zeroconf (or APIPA, Automatic Private IP Addressing) to automatically create the usable IP network without configuration.