IPRangeExplorer

121.0.0.0/8

Public

Class A — /8 prefix — 16,777,214 usable hosts

Network Address
121.0.0.0
Broadcast Address
121.255.255.255
Subnet Mask
255.0.0.0
Usable Hosts
16,777,214
First Usable IP
121.0.0.1
Last Usable IP
121.255.255.254
Total IPs
16,777,216
Prefix Length
/8

Network address — the base address of the block (121.0.0.0). All devices in this subnet share this prefix. Cannot be assigned to a host.

Broadcast address — packets sent to 121.255.255.255 are delivered to every device in the subnet. Also reserved — not assignable.

Usable hosts — the 16,777,214 addresses between those two that you can assign to servers, VMs, or interfaces.

Subnet mask — 255.0.0.0 is the dotted-decimal equivalent of /8. Older tools and Cisco configs use this format instead of CIDR slash notation.

Full Details

CIDR Notation 121.0.0.0/8
Network Address 121.0.0.0
Broadcast Address 121.255.255.255
Subnet Mask 255.0.0.0
Wildcard Mask 0.255.255.255
Prefix Length /8
IP Address Class Class A
Total IP Addresses 16,777,216
Usable Host Addresses 16,777,214
First Usable IP 121.0.0.1
Last Usable IP 121.255.255.254
Network (Hex) 0x79000000
Broadcast (Hex) 0x79FFFFFF
Address Type Public / Globally Routable

Binary Representation

Network Address
01111001 01111001.00000000.00000000.00000000
Subnet Mask
11111111.00000000.00000000.00000000

The first 8 bits (1s in the mask) identify the network. The remaining 24 bits identify hosts within the network.

Split into Equal Subnets

Split 121.0.0.0/8 into 2 equal /9 subnets (8,388,606 usable hosts each).

# CIDR Network First Usable Last Usable Broadcast Hosts
1 121.0.0.0/9 121.0.0.0 121.0.0.1 121.127.255.254 121.127.255.255 8,388,606
2 121.128.0.0/9 121.128.0.0 121.128.0.1 121.255.255.254 121.255.255.255 8,388,606

/8 Subnet Reference

Total IPs 16,777,216
Usable Hosts 16,777,214
Subnet Mask 255.0.0.0
Wildcard 0.255.255.255
Full /8 reference →

Related Ranges

Parent /7 block 120.0.0.0/7 Sibling /8 block 120.0.0.0/8

Adjacent Prefix Sizes

/6 67,108,862 hosts /7 33,554,430 hosts /8 16,777,214 hosts /9 8,388,606 hosts /10 4,194,302 hosts

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