21.252.137.0/25

Public

Class A — /25 prefix — 126 usable hosts

Network Address
21.252.137.0
Broadcast Address
21.252.137.127
Subnet Mask
255.255.255.128
Usable Hosts
126
First Usable IP
21.252.137.1
Last Usable IP
21.252.137.126
Total IPs
128
Prefix Length
/25

Network address — the base address of the block (21.252.137.0). All devices in this subnet share this prefix. Cannot be assigned to a host.

Broadcast address — packets sent to 21.252.137.127 are delivered to every device in the subnet. Also reserved — not assignable.

Usable hosts — the 126 addresses between those two that you can assign to servers, VMs, or interfaces.

Subnet mask255.255.255.128 is the dotted-decimal equivalent of /25. Older tools and Cisco configs use this format instead of CIDR slash notation.

Full Details

CIDR Notation 21.252.137.0/25
Network Address 21.252.137.0
Broadcast Address 21.252.137.127
Subnet Mask 255.255.255.128
Wildcard Mask 0.0.0.127
Prefix Length /25
IP Address Class Class A
Total IP Addresses 128
Usable Host Addresses 126
First Usable IP 21.252.137.1
Last Usable IP 21.252.137.126
Network (Hex) 0x15FC8900
Broadcast (Hex) 0x15FC897F
Address Type Public / Globally Routable

Binary Representation

Network Address
00010101.11111100.10001001 00010101.11111100.10001001.00000000
Subnet Mask
11111111.11111111.11111111.10000000

The first 25 bits (1s in the mask) identify the network. The remaining 7 bits identify hosts within the network.

Split into Equal Subnets

Split 21.252.137.0/25 into 2 equal /26 subnets (62 usable hosts each).

# CIDR Network First Usable Last Usable Broadcast Hosts
1 21.252.137.0/26 21.252.137.0 21.252.137.1 21.252.137.62 21.252.137.63 62
2 21.252.137.64/26 21.252.137.64 21.252.137.65 21.252.137.126 21.252.137.127 62

IP Address Sample

Showing first 16 of 128 total IPs.

21.252.137.0 net
21.252.137.1
21.252.137.2
21.252.137.3
21.252.137.4
21.252.137.5
21.252.137.6
21.252.137.7
21.252.137.8
21.252.137.9
21.252.137.10
21.252.137.11
21.252.137.12
21.252.137.13
21.252.137.14
21.252.137.15
… 112 more IPs …

/25 Subnet Reference

Total IPs 128
Usable Hosts 126
Subnet Mask 255.255.255.128
Wildcard 0.0.0.127

Calculate Another