CIDR prefix
/0
0.0.0.0
4,294,967,294 usable hosts · 4,294,967,296 addresses
The mask for /0 is 0.0.0.0 — 4,294,967,296 addresses, 4,294,967,294 usable hosts. The entire IPv4 space — the default route (0.0.0.0/0).
Mask
0.0.0.0
Wildcard
255.255.255.255
Addresses
4,294,967,296
Hosts
4,294,967,294
Worked example: 10.0.0.0/0
Network address0.0.0.0/0
Broadcast address255.255.255.255
First host0.0.0.1
Last host255.255.255.254
FAQ — /0
What is the subnet mask for /0?
The subnet mask for /0 is 0.0.0.0 (wildcard: 255.255.255.255). The first 0 bits are the network part, the remaining 32 are the host part.
How many hosts fit in a /0?
A /0 block holds 4,294,967,296 addresses, of which 4,294,967,294 are usable hosts (the network and broadcast addresses are excluded).
What is a /0 used for?
The entire IPv4 space — the default route (0.0.0.0/0).