🧩 VLSM (Variable Length Subnet Mask)

Tra cứu nhanh subnet mask, CIDR và các dải mạng phổ biến.

📘 Subnet Mask Information

CIDRSubnet MaskHostsNetworkBroadcast
/24255.255.255.0254192.168.1.0192.168.1.255
/25255.255.255.128126192.168.1.0192.168.1.127
/26255.255.255.19262192.168.1.0192.168.1.63
/27255.255.255.22430192.168.1.0192.168.1.31
/28255.255.255.24014192.168.1.0192.168.1.15
/29255.255.255.2486192.168.1.0192.168.1.7
/30255.255.255.2522192.168.1.0192.168.1.3

📗 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|

REFERENCES

cheats sheet others other