The foundation everything else runs on. Plan subnets, decode addresses and brush up on the fundamentals.
Everything here runs locally in your browser. Nothing you enter is sent to the server.
Enter an IPv4 address with a prefix (192.168.10.25/26) or a mask (192.168.10.25 255.255.255.192).
Split a network into equal smaller subnets, e.g. a /24 into four /26s.
Expand or compress an IPv6 address and see its prefix range, e.g. 2001:db8:abcd:12::1/64.
Paste a MAC address in any format to convert it and see what its bits mean.
Search common TCP/UDP ports by number, service or keyword.
| Port | Proto | Service | Notes |
|---|
Seven layers that describe how data moves from an application on one device to an application on another.
| Range | Purpose |
|---|---|
10.0.0.0/8 | Private (RFC 1918) |
172.16.0.0/12 | Private (RFC 1918) |
192.168.0.0/16 | Private (RFC 1918) |
100.64.0.0/10 | Carrier-grade NAT (RFC 6598) |
127.0.0.0/8 | Loopback |
169.254.0.0/16 | Link-local (APIPA) |
224.0.0.0/4 | Multicast |
192.0.2.0/24, 198.51.100.0/24, 203.0.113.0/24 | Documentation (RFC 5737) |
240.0.0.0/4 | Reserved |
| Prefix | Subnet mask | Usable hosts |
|---|