131.0.0.0/9

Public

Class B — /9 prefix — 8,388,606 usable hosts

Network Address
131.0.0.0
Broadcast Address
131.127.255.255
Subnet Mask
255.128.0.0
Usable Hosts
8,388,606
First Usable IP
131.0.0.1
Last Usable IP
131.127.255.254
Total IPs
8,388,608
Prefix Length
/9

Network address — the base address of the block (131.0.0.0). All devices in this subnet share this prefix. Cannot be assigned to a host.

Broadcast address — packets sent to 131.127.255.255 are delivered to every device in the subnet. Also reserved — not assignable.

Usable hosts — the 8,388,606 addresses between those two that you can assign to servers, VMs, or interfaces.

Subnet mask255.128.0.0 is the dotted-decimal equivalent of /9. Older tools and Cisco configs use this format instead of CIDR slash notation.

Full Details

CIDR Notation 131.0.0.0/9
Network Address 131.0.0.0
Broadcast Address 131.127.255.255
Subnet Mask 255.128.0.0
Wildcard Mask 0.127.255.255
Prefix Length /9
IP Address Class Class B
Total IP Addresses 8,388,608
Usable Host Addresses 8,388,606
First Usable IP 131.0.0.1
Last Usable IP 131.127.255.254
Network (Hex) 0x83000000
Broadcast (Hex) 0x837FFFFF
Address Type Public / Globally Routable

Binary Representation

Network Address
10000011 10000011.00000000.00000000.00000000
Subnet Mask
11111111.10000000.00000000.00000000

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

Split into Equal Subnets

Split 131.0.0.0/9 into 2 equal /10 subnets (4,194,302 usable hosts each).

# CIDR Network First Usable Last Usable Broadcast Hosts
1 131.0.0.0/10 131.0.0.0 131.0.0.1 131.63.255.254 131.63.255.255 4,194,302
2 131.64.0.0/10 131.64.0.0 131.64.0.1 131.127.255.254 131.127.255.255 4,194,302

/9 Subnet Reference

Total IPs 8,388,608
Usable Hosts 8,388,606
Subnet Mask 255.128.0.0
Wildcard 0.127.255.255

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