40.65.0.0/17

Public

Class A — /17 prefix — 32,766 usable hosts

Network Address
40.65.0.0
Broadcast Address
40.65.127.255
Subnet Mask
255.255.128.0
Usable Hosts
32,766
First Usable IP
40.65.0.1
Last Usable IP
40.65.127.254
Total IPs
32,768
Prefix Length
/17

Network address — the base address of the block (40.65.0.0). All devices in this subnet share this prefix. Cannot be assigned to a host.

Broadcast address — packets sent to 40.65.127.255 are delivered to every device in the subnet. Also reserved — not assignable.

Usable hosts — the 32,766 addresses between those two that you can assign to servers, VMs, or interfaces.

Subnet mask255.255.128.0 is the dotted-decimal equivalent of /17. Older tools and Cisco configs use this format instead of CIDR slash notation.

Full Details

CIDR Notation 40.65.0.0/17
Network Address 40.65.0.0
Broadcast Address 40.65.127.255
Subnet Mask 255.255.128.0
Wildcard Mask 0.0.127.255
Prefix Length /17
IP Address Class Class A
Total IP Addresses 32,768
Usable Host Addresses 32,766
First Usable IP 40.65.0.1
Last Usable IP 40.65.127.254
Network (Hex) 0x28410000
Broadcast (Hex) 0x28417FFF
Address Type Public / Globally Routable

Binary Representation

Network Address
00101000.01000001 00101000.01000001.00000000.00000000
Subnet Mask
11111111.11111111.10000000.00000000

The first 17 bits (1s in the mask) identify the network. The remaining 15 bits identify hosts within the network.

Split into Equal Subnets

Split 40.65.0.0/17 into 2 equal /18 subnets (16,382 usable hosts each).

# CIDR Network First Usable Last Usable Broadcast Hosts
1 40.65.0.0/18 40.65.0.0 40.65.0.1 40.65.63.254 40.65.63.255 16,382
2 40.65.64.0/18 40.65.64.0 40.65.64.1 40.65.127.254 40.65.127.255 16,382

/17 Subnet Reference

Total IPs 32,768
Usable Hosts 32,766
Subnet Mask 255.255.128.0
Wildcard 0.0.127.255

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