What is a network address?

A network address is an IP address that denotes an entire network as a whole, not a specific device within that network.

Put simply: a network address is the address of the network that devices belong to.

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#What a network address means

An IP address is logically divided into two parts:

• the network part
• the host part

A network address is an address in which:

• the entire host part consists of zeros
• it is used to denote the network itself

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#Example (IPv4)

Take the address:

192.168.1.10/24

• the /24 mask means:
  • 24 bits: network
  • 8 bits: hosts

Then:

• the network address will be:

192.168.1.0

The address 192.168.1.0:

• cannot be assigned to a device
• is used to denote the network 192.168.1.0/24

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#How a network address is calculated

A network address is obtained:

• using the subnet mask
• with a bitwise AND operation between the IP address and the mask

But for an interview, it is usually enough to understand that it is an address with a zero host part.

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#Why a network address is needed

A network address is used for:

• describing networks in routing tables
• determining whether devices are in the same network or in different ones
• configuring routers and subnets

Routers operate:

• not on individual IPs
• but on networks, denoted by network addresses

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#What is important to remember

• a network address:
  • is not assigned to a host
  • denotes a network
• next to it there is always:
  • a mask
  • or a prefix (/24, /16, and so on)