IPRangeExplorer

240.0.0.0/4

Public

The 240.0.0.0/4 block (240.0.0.0–255.255.255.254) is Class E address space, reserved for future use by RFC 1112. These addresses have never been allocated for general use on the public internet and are blocked by most routers and operating systems. 255.255.255.255 (the limited broadcast address) is the only address in this range with a defined purpose.

Network Address
240.0.0.0
Broadcast Address
255.255.255.255
Subnet Mask
240.0.0.0
Usable Hosts
268,435,454
First Usable IP
240.0.0.1
Last Usable IP
255.255.255.254
Total IPs
268,435,456
Prefix Length
/4

Network address — the base address of the block (240.0.0.0). All devices in this subnet share this prefix. Cannot be assigned to a host.

Broadcast address — packets sent to 255.255.255.255 are delivered to every device in the subnet. Also reserved — not assignable.

Usable hosts — the 268,435,454 addresses between those two that you can assign to servers, VMs, or interfaces.

Subnet mask — 240.0.0.0 is the dotted-decimal equivalent of /4. Older tools and Cisco configs use this format instead of CIDR slash notation.

Full Details

CIDR Notation 240.0.0.0/4
Network Address 240.0.0.0
Broadcast Address 255.255.255.255
Subnet Mask 240.0.0.0
Wildcard Mask 15.255.255.255
Prefix Length /4
IP Address Class Class E (Reserved)
Total IP Addresses 268,435,456
Usable Host Addresses 268,435,454
First Usable IP 240.0.0.1
Last Usable IP 255.255.255.254
Network (Hex) 0xF0000000
Broadcast (Hex) 0xFFFFFFFF
Address Type Public / Globally Routable

Binary Representation

Network Address
111 11110000.00000000.00000000.00000000
Subnet Mask
11110000.00000000.00000000.00000000

The first 4 bits (1s in the mask) identify the network. The remaining 28 bits identify hosts within the network.

Split into Equal Subnets

Split 240.0.0.0/4 into 2 equal /5 subnets (134,217,726 usable hosts each).

# CIDR Network First Usable Last Usable Broadcast Hosts
1 240.0.0.0/5 240.0.0.0 240.0.0.1 247.255.255.254 247.255.255.255 134,217,726
2 248.0.0.0/5 248.0.0.0 248.0.0.1 255.255.255.254 255.255.255.255 134,217,726

Common Use Cases

  • → No current production use — reserved
  • → Research into IPv4 address space exhaustion mitigation
  • → Some proposals to repurpose for private use (never adopted)

/4 Subnet Reference

Total IPs 268,435,456
Usable Hosts 268,435,454
Subnet Mask 240.0.0.0
Wildcard 15.255.255.255
Full /4 reference →

Related Ranges

Parent /3 block 224.0.0.0/3 Sibling /4 block 224.0.0.0/4

Adjacent Prefix Sizes

/2 1,073,741,822 hosts /3 536,870,910 hosts /4 268,435,454 hosts /5 134,217,726 hosts /6 67,108,862 hosts

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