🧩 VLSM (Variable Length Subnet Mask)¶
Tra cứu nhanh subnet mask, CIDR và các dải mạng phổ biến.
📘 Subnet Mask Information¶
| CIDR | Subnet Mask | Hosts | Network | Broadcast |
|---|---|---|---|---|
| /24 | 255.255.255.0 | 254 | 192.168.1.0 | 192.168.1.255 |
| /25 | 255.255.255.128 | 126 | 192.168.1.0 | 192.168.1.127 |
| /26 | 255.255.255.192 | 62 | 192.168.1.0 | 192.168.1.63 |
| /27 | 255.255.255.224 | 30 | 192.168.1.0 | 192.168.1.31 |
| /28 | 255.255.255.240 | 14 | 192.168.1.0 | 192.168.1.15 |
| /29 | 255.255.255.248 | 6 | 192.168.1.0 | 192.168.1.7 |
| /30 | 255.255.255.252 | 2 | 192.168.1.0 | 192.168.1.3 |
📗 IPv4 Subnet Summary Table¶
| Number of Addresses | Number of Bits | Prefix | Classful Notation | Mask |
|---|---|---|---|---|
| 1 | 0 | /32 | 255.255.255.255 | |
| 2 | 1 | /31 | 255.255.255.254 | |
| 4 | 2 | /30 | 255.255.255.252 | |
| 8 | 3 | /29 | 255.255.255.248 | |
| 16 | 4 | /28 | 255.255.255.240 | |
| 32 | 5 | /27 | 255.255.255.224 | |
| 64 | 6 | /26 | 255.255.255.192 | |
| 128 | 7 | /25 | 255.255.255.128 | |
| 256 | 8 | /24 | 1 C | 255.255.255.0 |
| 512 | 9 | /23 | 2 C | 255.255.254.0 |
| 1 K | 10 | /22 | 4 C | 255.255.252.0 |
| 2 K | 11 | /21 | 8 C | 255.255.248.0 |
| 4 K | 12 | /20 | 16 C | 255.255.240.0 |
| 8 K | 13 | /19 | 32 C | 255.255.224.0 |
| 16 K | 14 | /18 | 64 C | 255.255.192.0 |
| 32 K | 15 | /17 | 128 C | 255.255.128.0 |
| 64 K | 16 | /16 | 1 B | 255.255.0.0 |
| 128 K | 17 | /15 | 2 B | 255.254.0.0 |
| 256 K | 18 | /14 | 4 B | 255.252.0.0 |
| 512 K | 19 | /13 | 8 B | 255.248.0.0 |
| 1 M | 20 | /12 | 16 B | 255.240.0.0 |
| 2 M | 21 | /11 | 32 B | 255.224.0.0 |
| 4 M | 22 | /10 | 64 B | 255.192.0.0 |
| 8 M | 23 | /9 | 128 B | 255.128.0.0 |
| 16 M | 24 | /8 | 1 A | 255.0.0.0 |
| 32 M | 25 | /7 | 2 A | 254.0.0.0 |
| 64 M | 26 | /6 | 4 A | 252.0.0.0 |
| 128 M | 27 | /5 | 8 A | 248.0.0.0 |
| 256 M | 28 | /4 | 16 A | 240.0.0.0 |
| 512 M | 29 | /3 | 32 A | 224.0.0.0 |
| 1024 M | 30 | /2 | 64 A | 192.0.0.0 |