Subnet Buddy

v0.1 — homework 3

Inputs

Supports dotted-decimal only (no IPv6). Paste or type — auto-updates.
/24
Tip: change CIDR with slider or typed mask — they stay in sync.

Network
192.168.1.0
Broadcast
192.168.1.255
Usable hosts
254
Host range
192.168.1.1 — 192.168.1.254
Enter how many subnets you need (e.g. 4) and press Split — the app will create equal-sized subnets.

Binary

11000000.10101000.00000001.00001010
IP and Mask in binary (octets)

Mask / Wildcard

255.255.255.0 /24
Wildcard: 0.0.0.255

Counts

Total addresses: 256
Note: usable hosts exclude network & broadcast (except /31 & /32 special cases)

CIDR tips

/32 — single IP | /31 — two IPs (RFC)
Play around to learn subnets. This UI is intentionally a little messy ✦

Subnet list

click copy on any subnet

Raw / cmd examples

// example: Add route to network
sudo ip route add 192.168.1.0/24 via 192.168.1.1

// iptables-ish
-A FORWARD -s 192.168.1.0/24 -j ACCEPT