CIDR /17 Subnet Reference

A medium IPv4 subnet with 32.768 total addresses and 32.766 usable host addresses.

Subnet Mask255.255.128.0
Wildcard Mask0.0.127.255
Total IPs32.768
Usable Hosts32.766
Mask (Hex)FFFF8000
Host Bits15

Binary Breakdown

Subnet Mask11111111.11111111.10000000.00000000
Wildcard Mask00000000.00000000.01111111.11111111

Network bits (1s): 17 ·  Host bits (0s): 15

Common Uses for /17

  • Large campus network
  • 32,766 usable hosts

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Enter any IP address with /17 prefix to calculate exact network details.

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Frequently Asked Questions

What is the subnet mask for /17?

The subnet mask for /17 is 255.255.128.0 (hex: FFFF8000). In binary: 11111111.11111111.10000000.00000000.

How many hosts does a /17 subnet support?

A /17 subnet has 32.768 total addresses. Subtract 2 (network + broadcast) = 32.766 usable host addresses.

What is the wildcard mask for /17?

The wildcard mask (inverse mask) for /17 is 0.0.127.255. Used in Cisco ACLs and OSPF configurations to match the host portion of an address.

What is CIDR /17 used for?

Large campus network. 32,766 usable hosts.

Complete CIDR Reference Table /0–/32

PrefixSubnet MaskWildcardTotal IPsUsable Hosts
/00.0.0.0255.255.255.2554.294.967.2964.294.967.294
/1128.0.0.0127.255.255.2552.147.483.6482.147.483.646
/2192.0.0.063.255.255.2551.073.741.8241.073.741.822
/3224.0.0.031.255.255.255536.870.912536.870.910
/4240.0.0.015.255.255.255268.435.456268.435.454
/5248.0.0.07.255.255.255134.217.728134.217.726
/6252.0.0.03.255.255.25567.108.86467.108.862
/7254.0.0.01.255.255.25533.554.43233.554.430
/8255.0.0.00.255.255.25516.777.21616.777.214
/9255.128.0.00.127.255.2558.388.6088.388.606
/10255.192.0.00.63.255.2554.194.3044.194.302
/11255.224.0.00.31.255.2552.097.1522.097.150
/12255.240.0.00.15.255.2551.048.5761.048.574
/13255.248.0.00.7.255.255524.288524.286
/14255.252.0.00.3.255.255262.144262.142
/15255.254.0.00.1.255.255131.072131.070
/16255.255.0.00.0.255.25565.53665.534
/17255.255.128.00.0.127.25532.76832.766
/18255.255.192.00.0.63.25516.38416.382
/19255.255.224.00.0.31.2558.1928.190
/20255.255.240.00.0.15.2554.0964.094
/21255.255.248.00.0.7.2552.0482.046
/22255.255.252.00.0.3.2551.0241.022
/23255.255.254.00.0.1.255512510
/24255.255.255.00.0.0.255256254
/25255.255.255.1280.0.0.127128126
/26255.255.255.1920.0.0.636462
/27255.255.255.2240.0.0.313230
/28255.255.255.2400.0.0.151614
/29255.255.255.2480.0.0.786
/30255.255.255.2520.0.0.342
/31255.255.255.2540.0.0.122
/32255.255.255.2550.0.0.011