151.2.66.0/23

Public

Class B — /23 prefix — 510 usable hosts

Network Address

151.2.66.0

Broadcast Address

151.2.67.255

Subnet Mask

255.255.254.0

Usable Hosts

510

First Usable IP

151.2.66.1

Last Usable IP

151.2.67.254

Total IPs

512

Prefix Length

/23

Network address — the base address of the block (151.2.66.0). All devices in this subnet share this prefix. Cannot be assigned to a host.

Broadcast address — packets sent to 151.2.67.255 are delivered to every device in the subnet. Also reserved — not assignable.

Usable hosts — the 510 addresses between those two that you can assign to servers, VMs, or interfaces.

Subnet mask — 255.255.254.0 is the dotted-decimal equivalent of /23. Older tools and Cisco configs use this format instead of CIDR slash notation.

Full Details

CIDR Notation	151.2.66.0/23
Network Address	151.2.66.0
Broadcast Address	151.2.67.255
Subnet Mask	255.255.254.0
Wildcard Mask	0.0.1.255
Prefix Length	/23
IP Address Class	Class B
Total IP Addresses	512
Usable Host Addresses	510
First Usable IP	151.2.66.1
Last Usable IP	151.2.67.254
Network (Hex)	0x97024200
Broadcast (Hex)	0x970243FF
Address Type	Public / Globally Routable

Binary Representation

Network Address

10010111.00000010 10010111.00000010.01000010.00000000

Subnet Mask

11111111.11111111.11111110.00000000

The first 23 bits (1s in the mask) identify the network. The remaining 9 bits identify hosts within the network.

Split into Equal Subnets

Split 151.2.66.0/23 into 2 equal /24 subnets (254 usable hosts each).

#	CIDR	Network	First Usable	Last Usable	Broadcast	Hosts
1	151.2.66.0/24	151.2.66.0	151.2.66.1	151.2.66.254	151.2.66.255	254
2	151.2.67.0/24	151.2.67.0	151.2.67.1	151.2.67.254	151.2.67.255	254

Split 151.2.66.0/23 into 4 equal /25 subnets (126 usable hosts each).

#	CIDR	Network	First Usable	Last Usable	Broadcast	Hosts
1	151.2.66.0/25	151.2.66.0	151.2.66.1	151.2.66.126	151.2.66.127	126
2	151.2.66.128/25	151.2.66.128	151.2.66.129	151.2.66.254	151.2.66.255	126
3	151.2.67.0/25	151.2.67.0	151.2.67.1	151.2.67.126	151.2.67.127	126
4	151.2.67.128/25	151.2.67.128	151.2.67.129	151.2.67.254	151.2.67.255	126

Split 151.2.66.0/23 into 8 equal /26 subnets (62 usable hosts each).

#	CIDR	Network	First Usable	Last Usable	Broadcast	Hosts
1	151.2.66.0/26	151.2.66.0	151.2.66.1	151.2.66.62	151.2.66.63	62
2	151.2.66.64/26	151.2.66.64	151.2.66.65	151.2.66.126	151.2.66.127	62
3	151.2.66.128/26	151.2.66.128	151.2.66.129	151.2.66.190	151.2.66.191	62
4	151.2.66.192/26	151.2.66.192	151.2.66.193	151.2.66.254	151.2.66.255	62
5	151.2.67.0/26	151.2.67.0	151.2.67.1	151.2.67.62	151.2.67.63	62
6	151.2.67.64/26	151.2.67.64	151.2.67.65	151.2.67.126	151.2.67.127	62
7	151.2.67.128/26	151.2.67.128	151.2.67.129	151.2.67.190	151.2.67.191	62
8	151.2.67.192/26	151.2.67.192	151.2.67.193	151.2.67.254	151.2.67.255	62

Split 151.2.66.0/23 into 16 equal /27 subnets (30 usable hosts each).

#	CIDR	Network	First Usable	Last Usable	Broadcast	Hosts
1	151.2.66.0/27	151.2.66.0	151.2.66.1	151.2.66.30	151.2.66.31	30
2	151.2.66.32/27	151.2.66.32	151.2.66.33	151.2.66.62	151.2.66.63	30
3	151.2.66.64/27	151.2.66.64	151.2.66.65	151.2.66.94	151.2.66.95	30
4	151.2.66.96/27	151.2.66.96	151.2.66.97	151.2.66.126	151.2.66.127	30
5	151.2.66.128/27	151.2.66.128	151.2.66.129	151.2.66.158	151.2.66.159	30
6	151.2.66.160/27	151.2.66.160	151.2.66.161	151.2.66.190	151.2.66.191	30
7	151.2.66.192/27	151.2.66.192	151.2.66.193	151.2.66.222	151.2.66.223	30
8	151.2.66.224/27	151.2.66.224	151.2.66.225	151.2.66.254	151.2.66.255	30
9	151.2.67.0/27	151.2.67.0	151.2.67.1	151.2.67.30	151.2.67.31	30
10	151.2.67.32/27	151.2.67.32	151.2.67.33	151.2.67.62	151.2.67.63	30
11	151.2.67.64/27	151.2.67.64	151.2.67.65	151.2.67.94	151.2.67.95	30
12	151.2.67.96/27	151.2.67.96	151.2.67.97	151.2.67.126	151.2.67.127	30
13	151.2.67.128/27	151.2.67.128	151.2.67.129	151.2.67.158	151.2.67.159	30
14	151.2.67.160/27	151.2.67.160	151.2.67.161	151.2.67.190	151.2.67.191	30
15	151.2.67.192/27	151.2.67.192	151.2.67.193	151.2.67.222	151.2.67.223	30
16	151.2.67.224/27	151.2.67.224	151.2.67.225	151.2.67.254	151.2.67.255	30

/23 Subnet Reference

Total IPs 512

Usable Hosts 510

Subnet Mask 255.255.254.0

Wildcard 0.0.1.255

Full /23 reference →

Related Ranges

Parent /22 block 151.2.64.0/22 Sibling /23 block 151.2.64.0/23

Adjacent Prefix Sizes

/21 2,046 hosts /22 1,022 hosts /23 510 hosts /24 254 hosts /25 126 hosts