240.0.0.0/4 (Reserved (Former Class E))
ReservedRFC 1112
240.0.0.0/4 at a glance
| CIDR block | 240.0.0.0/4 |
|---|---|
| First address | 240.0.0.0 |
| Last address | 255.255.255.255 |
| Total addresses | 268,435,456 |
| Subnet mask | 240.0.0.0 |
| Prefix length | /4 |
| Type | Reserved |
| Publicly routable | No |
| Defined in | RFC 1112 |
Open in CIDR calculator/4 subnet details
What is 240.0.0.0/4 used for?
240.0.0.0/4 is the former Class E space, reserved for future use since RFC 1112. Most operating systems and routers refuse to route it, so it cannot be used on the internet. The top address, 255.255.255.255, is the limited broadcast address.
Common subnets of 240.0.0.0/4
Overlaps and conflicts
- Contains 255.255.255.255/32
FAQ
Can I use 240.0.0.0/4 addresses?
Not reliably. Many operating systems, routers and firewalls drop the range, and it is not allocated on the internet. Some providers use it internally, but it is not a fix for IPv4 shortage on general networks.
What was Class E?
The block 240.0.0.0 to 255.255.255.255, set aside as "experimental" in the classful addressing scheme and never opened for general use.