YurlieCIDR /9 Subnet Reference
A large IPv4 subnet with 8.388.608 total addresses and 8.388.606 usable host addresses.
Subnet Mask
255.128.0.0Wildcard Mask
0.127.255.255Total IPs
8.388.608Usable Hosts
8.388.606Mask (Hex)
FF800000Host Bits
23Binary Breakdown
Subnet Mask
11111111.10000000.00000000.00000000Wildcard Mask
00000000.01111111.11111111.11111111Network bits (1s): 9 · Host bits (0s): 23
Common Uses for /9
- Large ISP backbone blocks
- 8.4M addresses
Try the CIDR Calculator
Enter any IP address with /9 prefix to calculate exact network details.
Frequently Asked Questions
What is the subnet mask for /9?
The subnet mask for /9 is 255.128.0.0 (hex: FF800000). In binary: 11111111.10000000.00000000.00000000.
How many hosts does a /9 subnet support?
A /9 subnet has 8.388.608 total addresses. Subtract 2 (network + broadcast) = 8.388.606 usable host addresses.
What is the wildcard mask for /9?
The wildcard mask (inverse mask) for /9 is 0.127.255.255. Used in Cisco ACLs and OSPF configurations to match the host portion of an address.
What is CIDR /9 used for?
Large ISP backbone blocks. 8.4M addresses.
Complete CIDR Reference Table /0–/32
| Prefix | Subnet Mask | Wildcard | Total IPs | Usable Hosts |
|---|---|---|---|---|
| /0 | 0.0.0.0 | 255.255.255.255 | 4.294.967.296 | 4.294.967.294 |
| /1 | 128.0.0.0 | 127.255.255.255 | 2.147.483.648 | 2.147.483.646 |
| /2 | 192.0.0.0 | 63.255.255.255 | 1.073.741.824 | 1.073.741.822 |
| /3 | 224.0.0.0 | 31.255.255.255 | 536.870.912 | 536.870.910 |
| /4 | 240.0.0.0 | 15.255.255.255 | 268.435.456 | 268.435.454 |
| /5 | 248.0.0.0 | 7.255.255.255 | 134.217.728 | 134.217.726 |
| /6 | 252.0.0.0 | 3.255.255.255 | 67.108.864 | 67.108.862 |
| /7 | 254.0.0.0 | 1.255.255.255 | 33.554.432 | 33.554.430 |
| /8 | 255.0.0.0 | 0.255.255.255 | 16.777.216 | 16.777.214 |
| /9 | 255.128.0.0 | 0.127.255.255 | 8.388.608 | 8.388.606 |
| /10 | 255.192.0.0 | 0.63.255.255 | 4.194.304 | 4.194.302 |
| /11 | 255.224.0.0 | 0.31.255.255 | 2.097.152 | 2.097.150 |
| /12 | 255.240.0.0 | 0.15.255.255 | 1.048.576 | 1.048.574 |
| /13 | 255.248.0.0 | 0.7.255.255 | 524.288 | 524.286 |
| /14 | 255.252.0.0 | 0.3.255.255 | 262.144 | 262.142 |
| /15 | 255.254.0.0 | 0.1.255.255 | 131.072 | 131.070 |
| /16 | 255.255.0.0 | 0.0.255.255 | 65.536 | 65.534 |
| /17 | 255.255.128.0 | 0.0.127.255 | 32.768 | 32.766 |
| /18 | 255.255.192.0 | 0.0.63.255 | 16.384 | 16.382 |
| /19 | 255.255.224.0 | 0.0.31.255 | 8.192 | 8.190 |
| /20 | 255.255.240.0 | 0.0.15.255 | 4.096 | 4.094 |
| /21 | 255.255.248.0 | 0.0.7.255 | 2.048 | 2.046 |
| /22 | 255.255.252.0 | 0.0.3.255 | 1.024 | 1.022 |
| /23 | 255.255.254.0 | 0.0.1.255 | 512 | 510 |
| /24 | 255.255.255.0 | 0.0.0.255 | 256 | 254 |
| /25 | 255.255.255.128 | 0.0.0.127 | 128 | 126 |
| /26 | 255.255.255.192 | 0.0.0.63 | 64 | 62 |
| /27 | 255.255.255.224 | 0.0.0.31 | 32 | 30 |
| /28 | 255.255.255.240 | 0.0.0.15 | 16 | 14 |
| /29 | 255.255.255.248 | 0.0.0.7 | 8 | 6 |
| /30 | 255.255.255.252 | 0.0.0.3 | 4 | 2 |
| /31 | 255.255.255.254 | 0.0.0.1 | 2 | 2 |
| /32 | 255.255.255.255 | 0.0.0.0 | 1 | 1 |