IPRangeExplorer

172.19.128.0/17

Private (RFC 1918) RFC 1918

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

Network Address
172.19.128.0
Broadcast Address
172.19.255.255
Subnet Mask
255.255.128.0
Usable Hosts
32,766
First Usable IP
172.19.128.1
Last Usable IP
172.19.255.254
Total IPs
32,768
Prefix Length
/17

Network address — the base address of the block (172.19.128.0). All devices in this subnet share this prefix. Cannot be assigned to a host.

Broadcast address — packets sent to 172.19.255.255 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 mask — 255.255.128.0 is the dotted-decimal equivalent of /17. Older tools and Cisco configs use this format instead of CIDR slash notation.

Full Details

CIDR Notation 172.19.128.0/17
Network Address 172.19.128.0
Broadcast Address 172.19.255.255
Subnet Mask 255.255.128.0
Wildcard Mask 0.0.127.255
Prefix Length /17
IP Address Class Class B
Total IP Addresses 32,768
Usable Host Addresses 32,766
First Usable IP 172.19.128.1
Last Usable IP 172.19.255.254
Network (Hex) 0xAC138000
Broadcast (Hex) 0xAC13FFFF
Governing RFC RFC 1918
Address Type Private (RFC 1918)

Binary Representation

Network Address
10101100.00010011 10101100.00010011.10000000.00000000
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 172.19.128.0/17 into 2 equal /18 subnets (16,382 usable hosts each).

# CIDR Network First Usable Last Usable Broadcast Hosts
1 172.19.128.0/18 172.19.128.0 172.19.128.1 172.19.191.254 172.19.191.255 16,382
2 172.19.192.0/18 172.19.192.0 172.19.192.1 172.19.255.254 172.19.255.255 16,382

/17 Subnet Reference

Total IPs 32,768
Usable Hosts 32,766
Subnet Mask 255.255.128.0
Wildcard 0.0.127.255
Full /17 reference →

Related Ranges

Parent /16 block 172.19.0.0/16 Sibling /17 block 172.19.0.0/17

Adjacent Prefix Sizes

/15 131,070 hosts /16 65,534 hosts /17 32,766 hosts /18 16,382 hosts /19 8,190 hosts

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