18.161.0.0/20
PublicClass A — /20 prefix — 4,094 usable hosts
Network address — the base address of the block (18.161.0.0). All devices in this subnet share this prefix. Cannot be assigned to a host.
Broadcast address — packets sent to 18.161.15.255 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 | 18.161.0.0/20 |
| Network Address | 18.161.0.0 |
| Broadcast Address | 18.161.15.255 |
| 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 | 18.161.0.1 |
| Last Usable IP | 18.161.15.254 |
| Network (Hex) | 0x12A10000 |
| Broadcast (Hex) | 0x12A10FFF |
| 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.
Split into Equal Subnets
Split 18.161.0.0/20 into 2 equal /21 subnets (2,046 usable hosts each).
| # | CIDR | Network | First Usable | Last Usable | Broadcast | Hosts |
|---|---|---|---|---|---|---|
| 1 | 18.161.0.0/21 | 18.161.0.0 | 18.161.0.1 | 18.161.7.254 | 18.161.7.255 | 2,046 |
| 2 | 18.161.8.0/21 | 18.161.8.0 | 18.161.8.1 | 18.161.15.254 | 18.161.15.255 | 2,046 |
Split 18.161.0.0/20 into 4 equal /22 subnets (1,022 usable hosts each).
| # | CIDR | Network | First Usable | Last Usable | Broadcast | Hosts |
|---|---|---|---|---|---|---|
| 1 | 18.161.0.0/22 | 18.161.0.0 | 18.161.0.1 | 18.161.3.254 | 18.161.3.255 | 1,022 |
| 2 | 18.161.4.0/22 | 18.161.4.0 | 18.161.4.1 | 18.161.7.254 | 18.161.7.255 | 1,022 |
| 3 | 18.161.8.0/22 | 18.161.8.0 | 18.161.8.1 | 18.161.11.254 | 18.161.11.255 | 1,022 |
| 4 | 18.161.12.0/22 | 18.161.12.0 | 18.161.12.1 | 18.161.15.254 | 18.161.15.255 | 1,022 |
Split 18.161.0.0/20 into 8 equal /23 subnets (510 usable hosts each).
| # | CIDR | Network | First Usable | Last Usable | Broadcast | Hosts |
|---|---|---|---|---|---|---|
| 1 | 18.161.0.0/23 | 18.161.0.0 | 18.161.0.1 | 18.161.1.254 | 18.161.1.255 | 510 |
| 2 | 18.161.2.0/23 | 18.161.2.0 | 18.161.2.1 | 18.161.3.254 | 18.161.3.255 | 510 |
| 3 | 18.161.4.0/23 | 18.161.4.0 | 18.161.4.1 | 18.161.5.254 | 18.161.5.255 | 510 |
| 4 | 18.161.6.0/23 | 18.161.6.0 | 18.161.6.1 | 18.161.7.254 | 18.161.7.255 | 510 |
| 5 | 18.161.8.0/23 | 18.161.8.0 | 18.161.8.1 | 18.161.9.254 | 18.161.9.255 | 510 |
| 6 | 18.161.10.0/23 | 18.161.10.0 | 18.161.10.1 | 18.161.11.254 | 18.161.11.255 | 510 |
| 7 | 18.161.12.0/23 | 18.161.12.0 | 18.161.12.1 | 18.161.13.254 | 18.161.13.255 | 510 |
| 8 | 18.161.14.0/23 | 18.161.14.0 | 18.161.14.1 | 18.161.15.254 | 18.161.15.255 | 510 |
Split 18.161.0.0/20 into 16 equal /24 subnets (254 usable hosts each).
| # | CIDR | Network | First Usable | Last Usable | Broadcast | Hosts |
|---|---|---|---|---|---|---|
| 1 | 18.161.0.0/24 | 18.161.0.0 | 18.161.0.1 | 18.161.0.254 | 18.161.0.255 | 254 |
| 2 | 18.161.1.0/24 | 18.161.1.0 | 18.161.1.1 | 18.161.1.254 | 18.161.1.255 | 254 |
| 3 | 18.161.2.0/24 | 18.161.2.0 | 18.161.2.1 | 18.161.2.254 | 18.161.2.255 | 254 |
| 4 | 18.161.3.0/24 | 18.161.3.0 | 18.161.3.1 | 18.161.3.254 | 18.161.3.255 | 254 |
| 5 | 18.161.4.0/24 | 18.161.4.0 | 18.161.4.1 | 18.161.4.254 | 18.161.4.255 | 254 |
| 6 | 18.161.5.0/24 | 18.161.5.0 | 18.161.5.1 | 18.161.5.254 | 18.161.5.255 | 254 |
| 7 | 18.161.6.0/24 | 18.161.6.0 | 18.161.6.1 | 18.161.6.254 | 18.161.6.255 | 254 |
| 8 | 18.161.7.0/24 | 18.161.7.0 | 18.161.7.1 | 18.161.7.254 | 18.161.7.255 | 254 |
| 9 | 18.161.8.0/24 | 18.161.8.0 | 18.161.8.1 | 18.161.8.254 | 18.161.8.255 | 254 |
| 10 | 18.161.9.0/24 | 18.161.9.0 | 18.161.9.1 | 18.161.9.254 | 18.161.9.255 | 254 |
| 11 | 18.161.10.0/24 | 18.161.10.0 | 18.161.10.1 | 18.161.10.254 | 18.161.10.255 | 254 |
| 12 | 18.161.11.0/24 | 18.161.11.0 | 18.161.11.1 | 18.161.11.254 | 18.161.11.255 | 254 |
| 13 | 18.161.12.0/24 | 18.161.12.0 | 18.161.12.1 | 18.161.12.254 | 18.161.12.255 | 254 |
| 14 | 18.161.13.0/24 | 18.161.13.0 | 18.161.13.1 | 18.161.13.254 | 18.161.13.255 | 254 |
| 15 | 18.161.14.0/24 | 18.161.14.0 | 18.161.14.1 | 18.161.14.254 | 18.161.14.255 | 254 |
| 16 | 18.161.15.0/24 | 18.161.15.0 | 18.161.15.1 | 18.161.15.254 | 18.161.15.255 | 254 |