18.237.208.0/20
PublicClass A — /20 prefix — 4,094 usable hosts
Network address — the base address of the block (18.237.208.0). All devices in this subnet share this prefix. Cannot be assigned to a host.
Broadcast address — packets sent to 18.237.223.255 are delivered to every device in the subnet. Also reserved — not assignable.
Usable hosts — the 4,094 addresses between those two that you can assign to servers, VMs, or interfaces.
Subnet mask — 255.255.240.0 is the dotted-decimal equivalent of /20. Older tools and Cisco configs use this format instead of CIDR slash notation.
Full Details
| CIDR Notation | 18.237.208.0/20 |
| Network Address | 18.237.208.0 |
| Broadcast Address | 18.237.223.255 |
| Subnet Mask | 255.255.240.0 |
| Wildcard Mask | 0.0.15.255 |
| Prefix Length | /20 |
| IP Address Class | Class A |
| Total IP Addresses | 4,096 |
| Usable Host Addresses | 4,094 |
| First Usable IP | 18.237.208.1 |
| Last Usable IP | 18.237.223.254 |
| Network (Hex) | 0x12EDD000 |
| Broadcast (Hex) | 0x12EDDFFF |
| Address Type | Public / Globally Routable |
Binary Representation
The first 20 bits (1s in the mask) identify the network. The remaining 12 bits identify hosts within the network.
Subnet Breakdown — splitting into /21
This /20 block can be divided into 2 /21 subnets.
| CIDR | Network | Broadcast | First Usable | Last Usable | Hosts |
|---|---|---|---|---|---|
| 18.237.208.0/21 | 18.237.208.0 | 18.237.215.255 | 18.237.208.1 | 18.237.215.254 | 2,046 |
| 18.237.216.0/21 | 18.237.216.0 | 18.237.223.255 | 18.237.216.1 | 18.237.223.254 | 2,046 |