YurlieCIDR /31 Subnet Reference
Point-to-point link (RFC 3021) — 2 usable hosts, no broadcast address.
Subnet Mask
255.255.255.254Wildcard Mask
0.0.0.1Total IPs
2Usable Hosts
2Mask (Hex)
FFFFFFFEHost Bits
1Binary Breakdown
Subnet Mask
11111111.11111111.11111111.11111110Wildcard Mask
00000000.00000000.00000000.00000001Network bits (1s): 31 · Host bits (0s): 1
Common Uses for /31
- Point-to-point link (RFC 3021)
- No broadcast needed
- 2 usable hosts (no network/broadcast)
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Enter any IP address with /31 prefix to calculate exact network details.
Frequently Asked Questions
What is the subnet mask for /31?
The subnet mask for /31 is 255.255.255.254 (hex: FFFFFFFE). In binary: 11111111.11111111.11111111.11111110.
How many hosts does a /31 subnet support?
A /31 supports 2 usable hosts with no broadcast address (RFC 3021), used for point-to-point links.
What is the wildcard mask for /31?
The wildcard mask (inverse mask) for /31 is 0.0.0.1. Used in Cisco ACLs and OSPF configurations to match the host portion of an address.
What is CIDR /31 used for?
Point-to-point link (RFC 3021). No broadcast needed. 2 usable hosts (no network/broadcast).
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 |