100.86.20.0/25

Public

Class A — /25 prefix — 126 usable hosts

Network Address
100.86.20.0
Broadcast Address
100.86.20.127
Subnet Mask
255.255.255.128
Usable Hosts
126
First Usable IP
100.86.20.1
Last Usable IP
100.86.20.126
Total IPs
128
Prefix Length
/25

Network address — the base address of the block (100.86.20.0). All devices in this subnet share this prefix. Cannot be assigned to a host.

Broadcast address — packets sent to 100.86.20.127 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 100.86.20.0/25
Network Address 100.86.20.0
Broadcast Address 100.86.20.127
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 100.86.20.1
Last Usable IP 100.86.20.126
Network (Hex) 0x64561400
Broadcast (Hex) 0x6456147F
Address Type Public / Globally Routable

Binary Representation

Network Address
01100100.01010110.00010100 01100100.01010110.00010100.00000000
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 100.86.20.0/25 into 2 equal /26 subnets (62 usable hosts each).

# CIDR Network First Usable Last Usable Broadcast Hosts
1 100.86.20.0/26 100.86.20.0 100.86.20.1 100.86.20.62 100.86.20.63 62
2 100.86.20.64/26 100.86.20.64 100.86.20.65 100.86.20.126 100.86.20.127 62

IP Address Sample

Showing first 16 of 128 total IPs.

100.86.20.0 net
100.86.20.1
100.86.20.2
100.86.20.3
100.86.20.4
100.86.20.5
100.86.20.6
100.86.20.7
100.86.20.8
100.86.20.9
100.86.20.10
100.86.20.11
100.86.20.12
100.86.20.13
100.86.20.14
100.86.20.15
… 112 more IPs …

/25 Subnet Reference

Total IPs 128
Usable Hosts 126
Subnet Mask 255.255.255.128
Wildcard 0.0.0.127

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