Network - Subnet (Network Range)

A subnet is technically a division of an network by range of ip address

A subnet is also known as:

• a net range (ie 172.64.0.0 - 172.71.255.255)
• or a CIDR (different notation - ie 172.64.0.0/13)

In the internet age, all networks may be considered as subnet.

It is used to represent a subnet of hosts which can be reached over a network interface.

A SubNet is a partially qualified internet address in numeric (dotted quad) form, optionally followed by a slash and the netmask, specified as:

• the number of significant bits. See Classless Inter-Domain Routing (CIDR)
• or dot decimal notation

All hosts on a subnet have the same mask.

• in Classless Inter-Domain Routing (CIDR)

0.0.0.0/0

In a whois request, you can see the NetRange back (and the CIDR notation)

Example:

whois 172.70.250.60

NetRange:       172.64.0.0 - 172.71.255.255
CIDR:           172.64.0.0/13

A private subnet has no Internet access and can host the backend systems such as databases or application servers.

See Network - Private Network

A public subnet send and receive traffic directly from the internet.

See Network - Public Network

The maximum size of a network is given by the number of addresses that are possible with the remaining, least-significant bits below the mask prefix. See the mask table

Network - Partition

You can bind a whole subnet on one machine. See subnet binding